1HDPARM(8) System Manager's Manual HDPARM(8)
2
6 hdparm - get/set SATA/IDE device parameters
7
9 hdparm [options] [device ...]
10
12 hdparm provides a command line interface to various kernel interfaces
13 supported by the Linux SATA/PATA/SAS "libata" subsystem and the older
14 IDE driver subsystem. Many newer (2008 and later) USB drive enclosures
15 now also support "SAT" (SCSI-ATA Command Translation) and therefore may
16 also work with hdparm. E.g. recent WD "Passport" models and recent
17 NexStar-3 enclosures. Some options may work correctly only with the
18 latest kernels.
19
21 When no options are given, -acdgkmur is assumed. For "Get/set" op‐
22 tions, a query without the optional parameter (e.g. -d) will query
23 (get) the device state, and with a parameter (e.g., -d0) will set the
24 device state.
25 -a Get/set sector count for filesystem (software) read-ahead. This
27 is used to improve performance in sequential reads of large
28 files, by prefetching additional blocks in anticipation of them
29 being needed by the running task. Many IDE drives also have a
30 separate built-in read-ahead function, which augments this
31 filesystem (software) read-ahead function.
32 -A Get/set the IDE drive´s read-lookahead feature (usually ON by
34 default). Usage: -A0 (disable) or -A1 (enable).
35 -b Get/set bus state.
37 -B Get/set Advanced Power Management feature, if the drive supports
39 it. A low value means aggressive power management and a high
40 value means better performance. Possible settings range from
41 values 1 through 127 (which permit spin-down), and values 128
42 through 254 (which do not permit spin-down). The highest degree
43 of power management is attained with a setting of 1, and the
44 highest I/O performance with a setting of 254. A value of 255
45 tells hdparm to disable Advanced Power Management altogether on
46 the drive (not all drives support disabling it, but most do).
47 -c Get/set (E)IDE 32-bit I/O support. A numeric parameter can be
49 used to enable/disable 32-bit I/O support. Currently supported
50 values include 0 to disable 32-bit I/O support, 1 to enable
51 32-bit data transfers, and 3 to enable 32-bit data transfers
52 with a special sync sequence required by many chipsets. The
53 value 3 works with nearly all 32-bit IDE chipsets, but incurs
54 slightly more overhead. Note that "32-bit" refers to data
55 transfers across a PCI or VLB bus to the interface card only;
56 all (E)IDE drives still have only a 16-bit connection over the
57 ribbon cable from the interface card.
58 -C Check the current IDE power mode status, which will always be
60 one of unknown (drive does not support this command), ac‐
61 tive/idle (normal operation), standby (low power mode, drive has
62 spun down), or sleeping (lowest power mode, drive is completely
63 shut down). The -S, -y, -Y, and -Z options can be used to ma‐
64 nipulate the IDE power modes.
65 -d Get/set the "using_dma" flag for this drive. This option now
67 works with most combinations of drives and PCI interfaces which
68 support DMA and which are known to the kernel IDE driver. It is
69 also a good idea to use the appropriate -X option in combination
70 with -d1 to ensure that the drive itself is programmed for the
71 correct DMA mode, although most BIOSs should do this for you at
72 boot time. Using DMA nearly always gives the best performance,
73 with fast I/O throughput and low CPU usage. But there are at
74 least a few configurations of chipsets and drives for which DMA
75 does not make much of a difference, or may even slow things down
76 (on really messed up hardware!). Your mileage may vary.
77 --dco-freeze
79 DCO stands for Device Configuration Overlay, a way for vendors
80 to selectively disable certain features of a drive. The --dco-
81 freeze option will freeze/lock the current drive configuration,
82 thereby preventing software (or malware) from changing any DCO
83 settings until after the next power-on reset.
84 --dco-identify
86 Query and dump information regarding drive configuration set‐
87 tings which can be disabled by the vendor or OEM installer.
88 These settings show capabilities of the drive which might be
89 disabled by the vendor for "enhanced compatibility". When dis‐
90 abled, they are otherwise hidden and will not show in the -I
91 identify output. For example, system vendors sometimes disable
92 48_bit addressing on large drives, for compatibility (and loss
93 of capacity) with a specific BIOS. In such cases, --dco-iden‐
94 tify will show that the drive is 48_bit capable, but -I will not
95 show it, and nor will the drive accept 48_bit commands.
96 --dco-restore
98 Reset all drive settings, features, and accessible capacities
99 back to factory defaults and full capabilities. This command
100 will fail if DCO is frozen/locked, or if a -Np maximum size re‐
101 striction has also been set. This is EXTREMELY DANGEROUS and
102 will very likely cause massive loss of data. DO NOT USE THIS
103 COMMAND.
104 --direct
106 Use the kernel´s "O_DIRECT" flag when performing a -t timing
107 test. This bypasses the page cache, causing the reads to go di‐
108 rectly from the drive into hdparm's buffers, using so-called
109 "raw" I/O. In many cases, this can produce results that appear
110 much faster than the usual page cache method, giving a better
111 indication of raw device and driver performance.
112 --drq-hsm-error
114 VERY DANGEROUS, DON'T EVEN THINK ABOUT USING IT. This option
115 causes hdparm to issue an IDENTIFY command to the kernel, but
116 incorrectly marked as a "non-data" command. This results in the
117 drive being left with its DataReQust(DRQ) line "stuck" high.
118 This confuses the kernel drivers, and may crash the system imme‐
119 diately with massive data loss. The option exists to help in
120 testing and fortifying the kernel against similar real-world
121 drive malfunctions. VERY DANGEROUS, DO NOT USE!!
122 -D Enable/disable the on-drive defect management feature, whereby
124 the drive firmware tries to automatically manage defective sec‐
125 tors by relocating them to "spare" sectors reserved by the fac‐
126 tory for such. Control of this feature via the -D option is not
127 supported for most modern drives since ATA-4; thus this command
128 may fail.
129 -E Set cd/dvd drive speed. This is NOT necessary for regular oper‐
131 ation, as the drive will automatically switch speeds on its own.
132 But if you want to play with it, just supply a speed number af‐
133 ter the option, usually a number like 2 or 4. This can be use‐
134 ful in some cases, though, to smooth out DVD video playback.
135 -f Sync and flush the buffer cache for the device on exit. This
137 operation is also performed internally as part of the -t and -T
138 timings and other options.
139 --fallocate
141 This option currently works only on ext4 and xfs filesystem
142 types. When used, this must be the only option given. It re‐
143 quires two parameters: the desired file size in kilo-bytes (byte
144 count divided by 1024), followed by the pathname for the new
145 file. It will create a new file of the specified size, but
146 without actually having to write any data to the file. This
147 will normally complete very quickly, and without thrashing the
148 storage device.
149 E.g. Create a 10KByte file: hdparm --fallocate 10 temp_file
151 --fibmap
153 When used, this must be the only option given. It requires a
154 file path as a parameter, and will print out a list of the block
155 extents (sector ranges) occupied by that file on disk. Sector
156 numbers are given as absolute LBA numbers, referenced from sec‐
157 tor 0 of the physical device rather than from the partition or
158 filesystem. This information can then be used for a variety of
159 purposes, such as examining the degree of fragmenation of larger
160 files, or determining appropriate sectors to deliberately cor‐
161 rupt during fault-injection testing procedures.
162 This option uses the new FIEMAP (file extent map) ioctl() when
164 available, and falls back to the older FIBMAP (file block map)
165 ioctl() otherwise. Note that FIBMAP suffers from a 32-bit
166 block-number interface, and thus not work beyond 8TB or 16TB.
167 FIBMAP is also very slow, and does not deal well with preallo‐
168 cated uncommitted extents in ext4/xfs filesystems, unless a
169 sync() is done before using this option.
170 --fwdownload
172 When used, this should be the only option given. It requires a
173 file path immediately after the option, indicating where the new
174 drive firmware should be read from. The contents of this file
175 will be sent to the drive using the (S)ATA DOWNLOAD MICROCODE
176 command, using either transfer protocol 7 (entire file at once),
177 or, if the drive supports it, transfer protocol 3 (segmented
178 download). This command is EXTREMELY DANGEROUS and could de‐
179 stroy both the drive and all data on it. DO NOT USE THIS COM‐
180 MAND. The --fwdownload-mode3 , --fwdownload-mode3-max , and
181 --fwdownload-mode7 variations on basic --fwdownload allow over‐
182 riding automatic protocol detection in favour of forcing hdparm
183 to use a specific transfer protocol, for testing purposes only.
184 -F Flush the on-drive write cache buffer (older drives may not im‐
186 plement this).
187 -g Display the drive geometry (cylinders, heads, sectors), the size
189 (in sectors) of the device, and the starting offset (in sectors)
190 of the device from the beginning of the drive.
191 -h Display terse usage information (help).
193 -H Read the temperature from some (mostly Hitachi) drives. Also
195 reports if the temperature is within operating condition range
196 (this may not be reliable). Does not cause the drive to spin up
197 if idle.
198 -i Display the identification info which the kernel drivers (IDE,
200 libata) have stored from boot/configuration time. This may dif‐
201 fer from the current information obtainable directly from the
202 drive itself with the -I option. The data returned may or may
203 not be current, depending on activity since booting the system.
204 For a more detailed interpretation of the identification info,
205 refer to AT Attachment Interface for Disk Drives, ANSI ASC
206 X3T9.2 working draft, revision 4a, April 19/93, and later edi‐
207 tions.
208 --idle-immediate
210 Issue an ATA IDLE_IMMEDIATE command, to put the drive into a
211 lower power state. Usually the device remains spun-up.
212 --idle-unload
214 Issue an ATA IDLE_IMMEDIATE_WITH_UNLOAD command, to unload or
215 park the heads and put the drive into a lower power state. Usu‐
216 ally the device remains spun-up.
217 -I Request identification info directly from the drive, which is
219 displayed in a new expanded format with considerably more detail
220 than with the older -i option.
221 --Iraw <pathname>
223 This option dumps the drive's identify data in raw binary to the
224 specified file.
225 --Istdin
227 This is a special variation on the -I option, which accepts a
228 drive identification block as standard input instead of using a
229 /dev/hd* parameter. The format of this block must be exactly
230 the same as that found in the /proc/ide/*/hd*/identify "files",
231 or that produced by the --Istdout option described below. This
232 variation is designed for use with collected "libraries" of
233 drive identification information, and can also be used on ATAPI
234 drives which may give media errors with the standard mechanism.
235 When --Istdin is used, it must be the *only* parameter given.
236 Note that some information will be incomplete, as the drive LOG
237 PAGES are unavailable when --Istdin is used.
238 --Istdout
240 This option dumps the drive's identify data in hex to stdout, in
241 a format similar to that from /proc/ide/*/identify, and suitable
242 for later use with the --Istdin option.
243 -J Get/set the Western Digital (WD) Green Drive's "idle3" timeout
245 value. This timeout controls how often the drive parks its
246 heads and enters a low power consumption state. The factory de‐
247 fault is eight (8) seconds, which is a very poor choice for use
248 with Linux. Leaving it at the default will result in hundreds
249 of thousands of head load/unload cycles in a very short period
250 of time. The drive mechanism is only rated for 300,000 to
251 1,000,000 cycles, so leaving it at the default could result in
252 premature failure, not to mention the performance impact of the
253 drive often having to wake-up before doing routine I/O.
254 WD supply a WDIDLE3.EXE DOS utility for tweaking this setting,
256 and you should use that program instead of hdparm if at all pos‐
257 sible. The reverse-engineered implementation in hdparm is not
258 as complete as the original official program, even though it
259 does seem to work on at a least a few drives. A full power cy‐
260 cle is required for any change in setting to take effect, re‐
261 gardless of which program is used to tweak things.
262 A setting of 30 seconds is recommended for Linux use. Permitted
264 values are from 8 to 12 seconds, and from 30 to 300 seconds in
265 30-second increments. Specify a value of zero (0) to disable
266 the WD idle3 timer completely (NOT RECOMMENDED!).
267 -k Get/set the "keep_settings_over_reset" flag for the drive. When
269 this flag is set, the drive will preserve the -dmu settings over
270 a soft reset, (as done during the error recovery sequence).
271 This option defaults to off, to prevent drive reset loops which
272 could be caused by combinations of -dmu settings. The -k option
273 should therefore only be set after one has achieved confidence
274 in correct system operation with a chosen set of configuration
275 settings. In practice, all that is typically necessary to test
276 a configuration (prior to using -k) is to verify that the drive
277 can be read/written, and that no error logs (kernel messages)
278 are generated in the process (look in /var/log/messages on most
279 systems).
280 -K Set the drive´s "keep_features_over_reset" flag. Setting this
282 enables the drive to retain the settings for -APSWXZ over a soft
283 reset (as done during the error recovery sequence). Not all
284 drives support this feature.
285 -L Set the drive´s doorlock flag. Setting this to 1 will lock the
287 door mechanism of some removable hard drives (e.g. Syquest, ZIP,
288 Jazz..), and setting it to 0 will unlock the door mechanism.
289 Normally, Linux maintains the door locking mechanism automati‐
290 cally, depending on drive usage (locked whenever a filesystem is
291 mounted). But on system shutdown, this can be a nuisance if the
292 root partition is on a removable disk, since the root partition
293 is left mounted (read-only) after shutdown. So, by using this
294 command to unlock the door after the root filesystem is re‐
295 mounted read-only, one can then remove the cartridge from the
296 drive after shutdown.
297 -m Get/set sector count for multiple sector I/O on the drive. A
299 setting of 0 disables this feature. Multiple sector mode (aka
300 IDE Block Mode), is a feature of most modern IDE hard drives,
301 permitting the transfer of multiple sectors per I/O interrupt,
302 rather than the usual one sector per interrupt. When this fea‐
303 ture is enabled, it typically reduces operating system overhead
304 for disk I/O by 30-50%. On many systems, it also provides in‐
305 creased data throughput of anywhere from 5% to 50%. Some
306 drives, however (most notably the WD Caviar series), seem to run
307 slower with multiple mode enabled. Your mileage may vary. Most
308 drives support the minimum settings of 2, 4, 8, or 16 (sectors).
309 Larger settings may also be possible, depending on the drive. A
310 setting of 16 or 32 seems optimal on many systems. Western Dig‐
311 ital recommends lower settings of 4 to 8 on many of their
312 drives, due tiny (32kB) drive buffers and non-optimized buffer‐
313 ing algorithms. The -i option can be used to find the maximum
314 setting supported by an installed drive (look for MaxMultSect in
315 the output). Some drives claim to support multiple mode, but
316 lose data at some settings. Under rare circumstances, such
317 failures can result in massive filesystem corruption.
318 --make-bad-sector
320 Deliberately create a bad sector (aka. "media error") on the
321 disk. EXCEPTIONALLY DANGEROUS. DO NOT USE THIS OPTION!! This
322 can be useful for testing of device/RAID error recovery mecha‐
323 nisms. The sector number is given as a (base10) parameter after
324 the option. Depending on the device, hdparm will choose one of
325 two possible ATA commands for corrupting the sector. The
326 WRITE_LONG works on most drives, but only up to the 28-bit sec‐
327 tor boundary. Some very recent drives (2008) may support the
328 new WRITE_UNCORRECTABLE_EXT command, which works for any LBA48
329 sector. If available, hdparm will use that in preference to
330 WRITE_LONG. The WRITE_UNCORRECTABLE_EXT command itself presents
331 a choice of how the new bad sector should behave. By default,
332 it will look like any other bad sector, and the drive may take
333 some time to retry and fail on subsequent READs of the sector.
334 However, if a single letter f is prepended immediately in front
335 of the first digit of the sector number parameter, then hdparm
336 will issue a "flagged" WRITE_UNCORRECTABLE_EXT, which causes the
337 drive to merely flag the sector as bad (rather than genuinely
338 corrupt it), and subsequent READs of the sector will fail imme‐
339 diately (rather than after several retries). Note also that the
340 --repair-sector option can be used to restore (any) bad sectors
341 when they are no longer needed, including sectors that were gen‐
342 uinely bad (the drive will likely remap those to a fresh area on
343 the media).
344 -M Get/set Automatic Acoustic Management (AAM) setting. Most modern
346 harddisk drives have the ability to speed down the head move‐
347 ments to reduce their noise output. The possible values are be‐
348 tween 0 and 254. 128 is the most quiet (and therefore slowest)
349 setting and 254 the fastest (and loudest). Some drives have only
350 two levels (quiet / fast), while others may have different lev‐
351 els between 128 and 254. At the moment, most drives only sup‐
352 port 3 options, off, quiet, and fast. These have been assigned
353 the values 0, 128, and 254 at present, respectively, but integer
354 space has been incorporated for future expansion, should this
355 change.
356 -n Get or set the "ignore_write_errors" flag in the driver. Do NOT
358 play with this without grokking the driver source code first.
359 -N Get/set max visible number of sectors, also known as the Host
361 Protected Area setting. Without a parameter, -N displays the
362 current setting, which is reported as two values: the first
363 gives the current max sectors setting, and the second shows the
364 native (real) hardware limit for the disk. The difference be‐
365 tween these two values indicates how many sectors of the disk
366 are currently hidden from the operating system, in the form of a
367 Host Protected Area (HPA). This area is often used by computer
368 makers to hold diagnostic software, and/or a copy of the origi‐
369 nally provided operating system for recovery purposes. Another
370 possible use is to hide the true capacity of a very large disk
371 from a BIOS/system that cannot normally cope with drives of that
372 size (eg. most current {2010} BIOSs cannot deal with drives
373 larger than 2TB, so an HPA could be used to cause a 3TB drive to
374 report itself as a 2TB drive). To change the current max (VERY
375 DANGEROUS, DATA LOSS IS EXTREMELY LIKELY), a new value should be
376 provided (in base10) immediately following the -N option. This
377 value is specified as a count of sectors, rather than the "max
378 sector address" of the drive. Drives have the concept of a tem‐
379 porary (volatile) setting which is lost on the next hardware re‐
380 set, as well as a more permanent (non-volatile) value which sur‐
381 vives resets and power cycles. By default, -N affects only the
382 temporary (volatile) setting. To change the permanent (non-
383 volatile) value, prepend a leading p character immediately be‐
384 fore the first digit of the value. Drives are supposed to allow
385 only a single permanent change per session. A hardware reset
386 (or power cycle) is required before another permanent -N opera‐
387 tion can succeed. Note that any attempt to set this value may
388 fail if the disk is being accessed by other software at the same
389 time. This is because setting the value requires a pair of
390 back-to-back drive commands, but there is no way to prevent some
391 other command from being inserted between them by the kernel.
392 So if it fails initially, just try again. Kernel support for -N
393 is buggy for many adapter types across many kernel versions, in
394 that an incorrect (too small) max size value is sometimes re‐
395 ported. As of the 2.6.27 kernel, this does finally seem to be
396 working on most hardware.
397 --offset
399 Offsets to given number of GiB (1024*1024*1024) when performing
400 -t timings of device reads. Speed changes (about twice) along
401 many mechanical drives. Usually the maximum is at the begin‐
402 ning, but not always. Solid-state drives (SSDs) should show
403 similar timings regardless of offset.
404 -p Attempt to reprogram the IDE interface chipset for the specified
406 PIO mode, or attempt to auto-tune for the "best" PIO mode sup‐
407 ported by the drive. This feature is supported in the kernel
408 for only a few "known" chipsets, and even then the support is
409 iffy at best. Some IDE chipsets are unable to alter the PIO
410 mode for a single drive, in which case this option may cause the
411 PIO mode for both drives to be set. Many IDE chipsets support
412 either fewer or more than the standard six (0 to 5) PIO modes,
413 so the exact speed setting that is actually implemented will
414 vary by chipset/driver sophistication. Use with extreme cau‐
415 tion! This feature includes zero protection for the unwary, and
416 an unsuccessful outcome may result in severe filesystem corrup‐
417 tion!
418 -P Set the maximum sector count for the drive´s internal prefetch
420 mechanism. Not all drives support this feature, and it was
421 dropped from the official spec as of ATA-4.
422 --prefer-ata12
424 When using the SAT (SCSI ATA Translation) protocol, hdparm nor‐
425 mally prefers to use the 16-byte command format whenever possi‐
426 ble. But some USB drive enclosures don't work correctly with
427 16-byte commands. This option can be used to force use of the
428 smaller 12-byte command format with such drives. hdparm will
429 still revert to 16-byte commands for things that cannot be done
430 with the 12-byte format (e.g. sector accesses beyond 28-bits).
431 -q Handle the next option quietly, suppressing normal output (but
433 not error messages). This is useful for reducing screen clutter
434 when running from system startup scripts. Not applicable to the
435 -i or -v or -t or -T options.
436 -Q Get or set the device's command queue_depth, if supported by the
438 hardware. This only works with 2.6.xx (or later) kernels, and
439 only with device and driver combinations which support changing
440 the queue_depth. For SATA disks, this is the Native Command
441 Queuing (NCQ) queue depth.
442 -r Get/set read-only flag for the device. When set, Linux disal‐
444 lows write operations on the device.
445 -R Get/set Write-Read-Verify feature, if the drive supports it.
447 Usage: -R0 (disable) or -R1 (enable). This feature is intended
448 to have the drive firmware automatically read-back any data that
449 is written by software, to verify that the data was successfully
450 written. This is generally overkill, and can slow down disk
451 writes by as much as a factor of two (or more).
452 --read-sector
454 Reads from the specified sector number, and dumps the contents
455 in hex to standard output. The sector number must be given
456 (base10) after this option. hdparm will issue a low-level read
457 (completely bypassing the usual block layer read/write mecha‐
458 nisms) for the specified sector. This can be used to defini‐
459 tively check whether a given sector is bad (media error) or not
460 (doing so through the usual mechanisms can sometimes give false
461 positives).
462 --repair-sector
464 This is an alias for the --write-sector option. VERY DANGEROUS.
465 -s Enable/disable the power-on in standby feature, if supported by
467 the drive. VERY DANGEROUS. Do not use unless you are abso‐
468 lutely certain that both the system BIOS (or firmware) and the
469 operating system kernel (Linux >= 2.6.22) support probing for
470 drives that use this feature. When enabled, the drive is pow‐
471 ered-up in the standby mode to allow the controller to sequence
472 the spin-up of devices, reducing the instantaneous current draw
473 burden when many drives share a power supply. Primarily for use
474 in large RAID setups. This feature is usually disabled and the
475 drive is powered-up in the active mode (see -C above). Note
476 that a drive may also allow enabling this feature by a jumper.
477 Some SATA drives support the control of this feature by pin 11
478 of the SATA power connector. In these cases, this command may be
479 unsupported or may have no effect.
480 -S Put the drive into idle (low-power) mode, and also set the
482 standby (spindown) timeout for the drive. This timeout value is
483 used by the drive to determine how long to wait (with no disk
484 activity) before turning off the spindle motor to save power.
485 Under such circumstances, the drive may take as long as 30 sec‐
486 onds to respond to a subsequent disk access, though most drives
487 are much quicker. The encoding of the timeout value is somewhat
488 peculiar. A value of zero means "timeouts are disabled": the
489 device will not automatically enter standby mode. Values from 1
490 to 240 specify multiples of 5 seconds, yielding timeouts from 5
491 seconds to 20 minutes. Values from 241 to 251 specify from 1 to
492 11 units of 30 minutes, yielding timeouts from 30 minutes to 5.5
493 hours. A value of 252 signifies a timeout of 21 minutes. A
494 value of 253 sets a vendor-defined timeout period between 8 and
495 12 hours, and the value 254 is reserved. 255 is interpreted as
496 21 minutes plus 15 seconds. Note that some older drives may
497 have very different interpretations of these values.
498 --set-sector-size
500 For drives which support reconfiguring of the Logical Sector
501 Size, this flag can be used to specify the new desired sector
502 size in bytes. VERY DANGEROUS. This most likely will scramble
503 all data on the drive. The specified size must be one of 512,
504 520, 528, 4096, 4160, or 4224. Very few drives support values
505 other than 512 and 4096. Eg. hdparm --set-sector-size 4096
506 /dev/sdb
507 -t Perform timings of device reads for benchmark and comparison
509 purposes. For meaningful results, this operation should be re‐
510 peated 2-3 times on an otherwise inactive system (no other ac‐
511 tive processes) with at least a couple of megabytes of free mem‐
512 ory. This displays the speed of reading through the buffer
513 cache to the disk without any prior caching of data. This mea‐
514 surement is an indication of how fast the drive can sustain se‐
515 quential data reads under Linux, without any filesystem over‐
516 head. To ensure accurate measurements, the buffer cache is
517 flushed during the processing of -t using the BLKFLSBUF ioctl.
518 -T Perform timings of cache reads for benchmark and comparison pur‐
520 poses. For meaningful results, this operation should be re‐
521 peated 2-3 times on an otherwise inactive system (no other ac‐
522 tive processes) with at least a couple of megabytes of free mem‐
523 ory. This displays the speed of reading directly from the Linux
524 buffer cache without disk access. This measurement is essen‐
525 tially an indication of the throughput of the processor, cache,
526 and memory of the system under test.
527 --trim-sector-ranges
529 For Solid State Drives (SSDs). EXCEPTIONALLY DANGEROUS. DO NOT
530 USE THIS OPTION!! Tells the drive firmware to discard unneeded
531 data sectors, destroying any data that may have been present
532 within them. This makes those sectors available for immediate
533 use by the firmware's garbage collection mechanism, to improve
534 scheduling for wear-leveling of the flash media. This option
535 expects one or more sector range pairs immediately after the op‐
536 tion: an LBA starting address, a colon, and a sector count (max
537 65535), with no intervening spaces. EXCEPTIONALLY DANGEROUS. DO
538 NOT USE THIS OPTION!!
539 E.g. hdparm --trim-sector-ranges 1000:4 7894:16 /dev/sdz
541 --trim-sector-ranges-stdin
543 Identical to --trim-sector-ranges above, except the list of
544 lba:count pairs is read from stdin rather than being specified
545 on the command line. This can be used to avoid problems with
546 excessively long command lines. It also permits batching of
547 many more sector ranges into single commands to the drive, up to
548 the currently configured transfer limit (max_sectors_kb).
549 -u Get/set the interrupt-unmask flag for the drive. A setting of 1
551 permits the driver to unmask other interrupts during processing
552 of a disk interrupt, which greatly improves Linux´s responsive‐
553 ness and eliminates "serial port overrun" errors. Use this fea‐
554 ture with caution: some drive/controller combinations do not
555 tolerate the increased I/O latencies possible when this feature
556 is enabled, resulting in massive filesystem corruption. In par‐
557 ticular, CMD-640B and RZ1000 (E)IDE interfaces can be unreliable
558 (due to a hardware flaw) when this option is used with kernel
559 versions earlier than 2.0.13. Disabling the IDE prefetch fea‐
560 ture of these interfaces (usually a BIOS/CMOS setting) provides
561 a safe fix for the problem for use with earlier kernels.
562 -v Display some basic settings, similar to -acdgkmur for IDE. This
564 is also the default behaviour when no options are specified.
565 -V Display program version and exit immediately.
567 --verbose
569 Display extra diagnostics from some commands.
570 -w Perform a device reset (DANGEROUS). Do NOT use this option. It
572 exists for unlikely situations where a reboot might otherwise be
573 required to get a confused drive back into a useable state.
574 --write-sector
576 Writes zeros to the specified sector number. VERY DANGEROUS.
577 The sector number must be given (base10) after this option. hd‐
578 parm will issue a low-level write (completely bypassing the
579 usual block layer read/write mechanisms) to the specified sec‐
580 tor. This can be used to force a drive to repair a bad sector
581 (media error).
582 -W Get/set the IDE/SATA drive´s write-caching feature.
584 -X Set the IDE transfer mode for (E)IDE/ATA drives. This is typi‐
586 cally used in combination with -d1 when enabling DMA to/from a
587 drive on a supported interface chipset, where -X mdma2 is used
588 to select multiword DMA mode2 transfers and -X sdma1 is used to
589 select simple mode 1 DMA transfers. With systems which support
590 UltraDMA burst timings, -X udma2 is used to select UltraDMA
591 mode2 transfers (you´ll need to prepare the chipset for UltraDMA
592 beforehand). Apart from that, use of this option is seldom nec‐
593 essary since most/all modern IDE drives default to their fastest
594 PIO transfer mode at power-on. Fiddling with this can be both
595 needless and risky. On drives which support alternate transfer
596 modes, -X can be used to switch the mode of the drive only.
597 Prior to changing the transfer mode, the IDE interface should be
598 jumpered or programmed (see -p option) for the new mode setting
599 to prevent loss and/or corruption of data. Use this with ex‐
600 treme caution! For the PIO (Programmed Input/Output) transfer
601 modes used by Linux, this value is simply the desired PIO mode
602 number plus 8. Thus, a value of 09 sets PIO mode1, 10 enables
603 PIO mode2, and 11 selects PIO mode3. Setting 00 restores the
604 drive´s "default" PIO mode, and 01 disables IORDY. For multi‐
605 word DMA, the value used is the desired DMA mode number plus 32.
606 for UltraDMA, the value is the desired UltraDMA mode number plus
607 64.
608 -y Force an IDE drive to immediately enter the low power consump‐
610 tion standby mode, usually causing it to spin down. The current
611 power mode status can be checked using the -C option.
612 -Y Force an IDE drive to immediately enter the lowest power con‐
614 sumption sleep mode, causing it to shut down completely. A hard
615 or soft reset is required before the drive can be accessed again
616 (the Linux IDE driver will automatically handle issuing a reset
617 if/when needed). The current power mode status can be checked
618 using the -C option.
619 -z Force a kernel re-read of the partition table of the specified
621 device(s).
622 -Z Disable the automatic power-saving function of certain Seagate
624 drives (ST3xxx models?), to prevent them from idling/spinning-
625 down at inconvenient times.
626 ATA Security Feature Set
629 These switches are DANGEROUS to experiment with, and might not work
631 with some kernels. USE AT YOUR OWN RISK.
632 --security-help
634 Display terse usage info for all of the --security-* options.
635 --security-freeze
637 Freeze the drive´s security settings. The drive does not accept
638 any security commands until next power-on reset. Use this func‐
639 tion in combination with --security-unlock to protect drive from
640 any attempt to set a new password. Can be used standalone, too.
641 No other options are permitted on the command line with this
642 one.
643 --security-prompt-for-password
645 Prompt for the --security PWD rather than getting from the com‐
646 mand line args. This avoids having passwords show up in shell
647 history or in /proc/self/cmdline during execution.
648 --security-unlock PWD
650 Unlock the drive, using password PWD. Password is given as an
651 ASCII string and is padded with NULs to reach 32 bytes. The ap‐
652 plicable drive password is selected with the --user-master
653 switch (default is "user" password). No other options are per‐
654 mitted on the command line with this one.
655 --security-set-pass PWD
657 Lock the drive, using password PWD (Set Password) (DANGEROUS).
658 Password is given as an ASCII string and is padded with NULs to
659 reach 32 bytes. Use the special password NULL to set an empty
660 password. The applicable drive password is selected with the
661 --user-master switch (default is "user" password) and the appli‐
662 cable security mode with the --security-mode switch. No other
663 options are permitted on the command line with this one.
664 --security-disable PWD
666 Disable drive locking, using password PWD. Password is given as
667 an ASCII string and is padded with NULs to reach 32 bytes. The
668 applicable drive password is selected with the --user-master
669 switch (default is "user" password). No other options are per‐
670 mitted on the command line with this one.
671 --security-erase PWD
673 Erase (locked) drive, using password PWD (DANGEROUS). Password
674 is given as an ASCII string and is padded with NULs to reach 32
675 bytes. Use the special password NULL to represent an empty
676 password. The applicable drive password is selected with the
677 --user-master switch (default is "user" password). No other op‐
678 tions are permitted on the command line with this one.
679 --security-erase-enhanced PWD
681 Enhanced erase (locked) drive, using password PWD (DANGEROUS).
682 Password is given as an ASCII string and is padded with NULs to
683 reach 32 bytes. The applicable drive password is selected with
684 the --user-master switch (default is "user" password). No other
685 options are permitted on the command line with this one.
686 --user-master USER
688 Specifies which password (user/master) to select. Defaults to
689 user password. Only useful in combination with --security-un‐
690 lock, --security-set-pass, --security-disable, --security-erase
691 or --security-erase-enhanced.
692 u user password
693 m master password
694 --security-mode MODE
697 Specifies which security mode (high/maximum) to set. Defaults
698 to high. Only useful in combination with --security-set-pass.
699 h high security
700 m maximum security
701 THIS FEATURE IS EXPERIMENTAL AND NOT WELL TESTED. USE AT YOUR
703 OWN RISK.
704
706 /etc/hdparm.conf
707
709 As noted above, the -m sectcount and -u 1 options should be used with
710 caution at first, preferably on a read-only filesystem. Most drives
711 work well with these features, but a few drive/controller combinations
712 are not 100% compatible. Filesystem corruption may result. Backup ev‐
713 erything before experimenting!
714 Some options (e.g. -r for SCSI) may not work with old kernels as neces‐
716 sary ioctl()´s were not supported.
717 Although this utility is intended primarily for use with SATA/IDE hard
719 disk devices, several of the options are also valid (and permitted) for
720 use with SCSI hard disk devices and MFM/RLL hard disks with XT inter‐
721 faces.
722 The Linux kernel up until 2.6.12 (and probably later) doesn´t handle
724 the security unlock and disable commands gracefully and will segfault
725 and in some cases even panic. The security commands however might in‐
726 deed have been executed by the drive. This poor kernel behaviour makes
727 the PIO data security commands rather useless at the moment.
728 Note that the "security erase" and "security disable" commands have
730 been implemented as two consecutive PIO data commands and will not suc‐
731 ceed on a locked drive because the second command will not be issued
732 after the segfault. See the code for hints how patch it to work around
733 this problem. Despite the segfault it is often still possible to run
734 two instances of hdparm consecutively and issue the two necessary com‐
735 mands that way.
736
738 hdparm has been written by Mark Lord <mlord@pobox.com>, the original
739 primary developer and maintainer of the (E)IDE driver for Linux, and
740 current contributor to the libata subsystem, along with suggestions and
741 patches from many netfolk.
742 The disable Seagate auto-powersaving code is courtesy of Tomi Leppikan‐
744 gas(tomilepp@paju.oulu.fi).
745 Security freeze command by Benjamin Benz, 2005.
747 PIO data out security commands by Leonard den Ottolander, 2005. Some
749 other parts by Benjamin Benz and others.
750
752 http://www.t13.org/ Technical Committee T13 AT Attachment (ATA/ATAPI)
753 Interface.
754 http://www.serialata.org/ Serial ATA International Organization.
756 http://www.compactflash.org/ CompactFlash Association.
758Version 9.65 Sep 2022 HDPARM(8)