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"
22 options, 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),
61 active/idle (normal operation), standby (low power mode, drive
62 has spun down), or sleeping (lowest power mode, drive is com‐
63 pletely shut down). The -S, -y, -Y, and -Z options can be used
64 to manipulate 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
101 restriction 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
108 directly 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
133 after the option, usually a number like 2 or 4. This can be
134 useful 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
143 requires two parameters: the desired file size in kilo-bytes
144 (byte count divided by 1024), followed by the pathname for the
145 new 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
179 destroy 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
186 implement 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 --Istdin
223 This is a special variation on the -I option, which accepts a
224 drive identification block as standard input instead of using a
225 /dev/hd* parameter. The format of this block must be exactly
226 the same as that found in the /proc/ide/*/hd*/identify "files",
227 or that produced by the --Istdout option described below. This
228 variation is designed for use with collected "libraries" of
229 drive identification information, and can also be used on ATAPI
230 drives which may give media errors with the standard mechanism.
231 When --Istdin is used, it must be the *only* parameter given.
232 --Istdout
234 This option dumps the drive's identify data in hex to stdout, in
235 a format similar to that from /proc/ide/*/identify, and suitable
236 for later use with the --Istdin option.
237 -J Get/set the Western Digital (WD) Green Drive's "idle3" timeout
239 value. This timeout controls how often the drive parks its
240 heads and enters a low power consumption state. The factory
241 default is eight (8) seconds, which is a very poor choice for
242 use with Linux. Leaving it at the default will result in hun‐
243 dreds of thousands of head load/unload cycles in a very short
244 period of time. The drive mechanism is only rated for 300,000
245 to 1,000,000 cycles, so leaving it at the default could result
246 in premature failure, not to mention the performance impact of
247 the drive often having to wake-up before doing routine I/O.
248 WD supply a WDIDLE3.EXE DOS utility for tweaking this setting,
250 and you should use that program instead of hdparm if at all pos‐
251 sible. The reverse-engineered implementation in hdparm is not
252 as complete as the original official program, even though it
253 does seem to work on at a least a few drives. A full power
254 cycle is required for any change in setting to take effect,
255 regardless of which program is used to tweak things.
256 A setting of 30 seconds is recommended for Linux use. Permitted
258 values are from 8 to 12 seconds, and from 30 to 300 seconds in
259 30-second increments. Specify a value of zero (0) to disable
260 the WD idle3 timer completely (NOT RECOMMENDED!).
261 -k Get/set the "keep_settings_over_reset" flag for the drive. When
263 this flag is set, the drive will preserve the -dmu settings over
264 a soft reset, (as done during the error recovery sequence).
265 This option defaults to off, to prevent drive reset loops which
266 could be caused by combinations of -dmu settings. The -k option
267 should therefore only be set after one has achieved confidence
268 in correct system operation with a chosen set of configuration
269 settings. In practice, all that is typically necessary to test
270 a configuration (prior to using -k) is to verify that the drive
271 can be read/written, and that no error logs (kernel messages)
272 are generated in the process (look in /var/log/messages on most
273 systems).
274 -K Set the drive´s "keep_features_over_reset" flag. Setting this
276 enables the drive to retain the settings for -APSWXZ over a soft
277 reset (as done during the error recovery sequence). Not all
278 drives support this feature.
279 -L Set the drive´s doorlock flag. Setting this to 1 will lock the
281 door mechanism of some removable hard drives (e.g. Syquest, ZIP,
282 Jazz..), and setting it to 0 will unlock the door mechanism.
283 Normally, Linux maintains the door locking mechanism automati‐
284 cally, depending on drive usage (locked whenever a filesystem is
285 mounted). But on system shutdown, this can be a nuisance if the
286 root partition is on a removable disk, since the root partition
287 is left mounted (read-only) after shutdown. So, by using this
288 command to unlock the door after the root filesystem is
289 remounted read-only, one can then remove the cartridge from the
290 drive after shutdown.
291 -m Get/set sector count for multiple sector I/O on the drive. A
293 setting of 0 disables this feature. Multiple sector mode (aka
294 IDE Block Mode), is a feature of most modern IDE hard drives,
295 permitting the transfer of multiple sectors per I/O interrupt,
296 rather than the usual one sector per interrupt. When this fea‐
297 ture is enabled, it typically reduces operating system overhead
298 for disk I/O by 30-50%. On many systems, it also provides
299 increased data throughput of anywhere from 5% to 50%. Some
300 drives, however (most notably the WD Caviar series), seem to run
301 slower with multiple mode enabled. Your mileage may vary. Most
302 drives support the minimum settings of 2, 4, 8, or 16 (sectors).
303 Larger settings may also be possible, depending on the drive. A
304 setting of 16 or 32 seems optimal on many systems. Western Dig‐
305 ital recommends lower settings of 4 to 8 on many of their
306 drives, due tiny (32kB) drive buffers and non-optimized buffer‐
307 ing algorithms. The -i option can be used to find the maximum
308 setting supported by an installed drive (look for MaxMultSect in
309 the output). Some drives claim to support multiple mode, but
310 lose data at some settings. Under rare circumstances, such
311 failures can result in massive filesystem corruption.
312 --make-bad-sector
314 Deliberately create a bad sector (aka. "media error") on the
315 disk. EXCEPTIONALLY DANGEROUS. DO NOT USE THIS OPTION!! This
316 can be useful for testing of device/RAID error recovery mecha‐
317 nisms. The sector number is given as a (base10) parameter after
318 the option. Depending on the device, hdparm will choose one of
319 two possible ATA commands for corrupting the sector. The
320 WRITE_LONG works on most drives, but only up to the 28-bit sec‐
321 tor boundary. Some very recent drives (2008) may support the
322 new WRITE_UNCORRECTABLE_EXT command, which works for any LBA48
323 sector. If available, hdparm will use that in preference to
324 WRITE_LONG. The WRITE_UNCORRECTABLE_EXT command itself presents
325 a choice of how the new bad sector should behave. By default,
326 it will look like any other bad sector, and the drive may take
327 some time to retry and fail on subsequent READs of the sector.
328 However, if a single letter f is prepended immediately in front
329 of the first digit of the sector number parameter, then hdparm
330 will issue a "flagged" WRITE_UNCORRECTABLE_EXT, which causes the
331 drive to merely flag the sector as bad (rather than genuinely
332 corrupt it), and subsequent READs of the sector will fail imme‐
333 diately (rather than after several retries). Note also that the
334 --repair-sector option can be used to restore (any) bad sectors
335 when they are no longer needed, including sectors that were gen‐
336 uinely bad (the drive will likely remap those to a fresh area on
337 the media).
338 -M Get/set Automatic Acoustic Management (AAM) setting. Most modern
340 harddisk drives have the ability to speed down the head move‐
341 ments to reduce their noise output. The possible values are
342 between 0 and 254. 128 is the most quiet (and therefore slowest)
343 setting and 254 the fastest (and loudest). Some drives have only
344 two levels (quiet / fast), while others may have different lev‐
345 els between 128 and 254. At the moment, most drives only sup‐
346 port 3 options, off, quiet, and fast. These have been assigned
347 the values 0, 128, and 254 at present, respectively, but integer
348 space has been incorporated for future expansion, should this
349 change.
350 -n Get or set the "ignore_write_errors" flag in the driver. Do NOT
352 play with this without grokking the driver source code first.
353 -N Get/set max visible number of sectors, also known as the Host
355 Protected Area setting. Without a parameter, -N displays the
356 current setting, which is reported as two values: the first
357 gives the current max sectors setting, and the second shows the
358 native (real) hardware limit for the disk. The difference
359 between these two values indicates how many sectors of the disk
360 are currently hidden from the operating system, in the form of a
361 Host Protected Area (HPA). This area is often used by computer
362 makers to hold diagnostic software, and/or a copy of the origi‐
363 nally provided operating system for recovery purposes. Another
364 possible use is to hide the true capacity of a very large disk
365 from a BIOS/system that cannot normally cope with drives of that
366 size (eg. most current {2010} BIOSs cannot deal with drives
367 larger than 2TB, so an HPA could be used to cause a 3TB drive to
368 report itself as a 2TB drive). To change the current max (VERY
369 DANGEROUS, DATA LOSS IS EXTREMELY LIKELY), a new value should be
370 provided (in base10) immediately following the -N option. This
371 value is specified as a count of sectors, rather than the "max
372 sector address" of the drive. Drives have the concept of a tem‐
373 porary (volatile) setting which is lost on the next hardware
374 reset, as well as a more permanent (non-volatile) value which
375 survives resets and power cycles. By default, -N affects only
376 the temporary (volatile) setting. To change the permanent (non-
377 volatile) value, prepend a leading p character immediately
378 before the first digit of the value. Drives are supposed to
379 allow only a single permanent change per session. A hardware
380 reset (or power cycle) is required before another permanent -N
381 operation can succeed. Note that any attempt to set this value
382 may fail if the disk is being accessed by other software at the
383 same time. This is because setting the value requires a pair of
384 back-to-back drive commands, but there is no way to prevent some
385 other command from being inserted between them by the kernel.
386 So if it fails initially, just try again. Kernel support for -N
387 is buggy for many adapter types across many kernel versions, in
388 that an incorrect (too small) max size value is sometimes
389 reported. As of the 2.6.27 kernel, this does finally seem to be
390 working on most hardware.
391 --offset
393 Offsets to given number of GiB (1024*1024*1024) when performing
394 -t timings of device reads. Speed changes (about twice) along
395 many mechanical drives. Usually the maximum is at the begin‐
396 ning, but not always. Solid-state drives (SSDs) should show
397 similar timings regardless of offset.
398 -p Attempt to reprogram the IDE interface chipset for the specified
400 PIO mode, or attempt to auto-tune for the "best" PIO mode sup‐
401 ported by the drive. This feature is supported in the kernel
402 for only a few "known" chipsets, and even then the support is
403 iffy at best. Some IDE chipsets are unable to alter the PIO
404 mode for a single drive, in which case this option may cause the
405 PIO mode for both drives to be set. Many IDE chipsets support
406 either fewer or more than the standard six (0 to 5) PIO modes,
407 so the exact speed setting that is actually implemented will
408 vary by chipset/driver sophistication. Use with extreme cau‐
409 tion! This feature includes zero protection for the unwary, and
410 an unsuccessful outcome may result in severe filesystem corrup‐
411 tion!
412 -P Set the maximum sector count for the drive´s internal prefetch
414 mechanism. Not all drives support this feature, and it was
415 dropped from the official spec as of ATA-4.
416 --prefer-ata12
418 When using the SAT (SCSI ATA Translation) protocol, hdparm nor‐
419 mally prefers to use the 16-byte command format whenever possi‐
420 ble. But some USB drive enclosures don't work correctly with
421 16-byte commands. This option can be used to force use of the
422 smaller 12-byte command format with such drives. hdparm will
423 still revert to 16-byte commands for things that cannot be done
424 with the 12-byte format (e.g. sector accesses beyond 28-bits).
425 -q Handle the next option quietly, suppressing normal output (but
427 not error messages). This is useful for reducing screen clutter
428 when running from system startup scripts. Not applicable to the
429 -i or -v or -t or -T options.
430 -Q Get or set the device's command queue_depth, if supported by the
432 hardware. This only works with 2.6.xx (or later) kernels, and
433 only with device and driver combinations which support changing
434 the queue_depth. For SATA disks, this is the Native Command
435 Queuing (NCQ) queue depth.
436 -r Get/set read-only flag for the device. When set, Linux disal‐
438 lows write operations on the device.
439 -R Get/set Write-Read-Verify feature, if the drive supports it.
441 Usage: -R0 (disable) or -R1 (enable). This feature is intended
442 to have the drive firmware automatically read-back any data that
443 is written by software, to verify that the data was successfully
444 written. This is generally overkill, and can slow down disk
445 writes by as much as a factor of two (or more).
446 --read-sector
448 Reads from the specified sector number, and dumps the contents
449 in hex to standard output. The sector number must be given
450 (base10) after this option. hdparm will issue a low-level read
451 (completely bypassing the usual block layer read/write mecha‐
452 nisms) for the specified sector. This can be used to defini‐
453 tively check whether a given sector is bad (media error) or not
454 (doing so through the usual mechanisms can sometimes give false
455 positives).
456 --repair-sector
458 This is an alias for the --write-sector option. VERY DANGEROUS.
459 -s Enable/disable the power-on in standby feature, if supported by
461 the drive. VERY DANGEROUS. Do not use unless you are abso‐
462 lutely certain that both the system BIOS (or firmware) and the
463 operating system kernel (Linux >= 2.6.22) support probing for
464 drives that use this feature. When enabled, the drive is pow‐
465 ered-up in the standby mode to allow the controller to sequence
466 the spin-up of devices, reducing the instantaneous current draw
467 burden when many drives share a power supply. Primarily for use
468 in large RAID setups. This feature is usually disabled and the
469 drive is powered-up in the active mode (see -C above). Note
470 that a drive may also allow enabling this feature by a jumper.
471 Some SATA drives support the control of this feature by pin 11
472 of the SATA power connector. In these cases, this command may be
473 unsupported or may have no effect.
474 -S Put the drive into idle (low-power) mode, and also set the
476 standby (spindown) timeout for the drive. This timeout value is
477 used by the drive to determine how long to wait (with no disk
478 activity) before turning off the spindle motor to save power.
479 Under such circumstances, the drive may take as long as 30 sec‐
480 onds to respond to a subsequent disk access, though most drives
481 are much quicker. The encoding of the timeout value is somewhat
482 peculiar. A value of zero means "timeouts are disabled": the
483 device will not automatically enter standby mode. Values from 1
484 to 240 specify multiples of 5 seconds, yielding timeouts from 5
485 seconds to 20 minutes. Values from 241 to 251 specify from 1 to
486 11 units of 30 minutes, yielding timeouts from 30 minutes to 5.5
487 hours. A value of 252 signifies a timeout of 21 minutes. A
488 value of 253 sets a vendor-defined timeout period between 8 and
489 12 hours, and the value 254 is reserved. 255 is interpreted as
490 21 minutes plus 15 seconds. Note that some older drives may
491 have very different interpretations of these values.
492 -t Perform timings of device reads for benchmark and comparison
494 purposes. For meaningful results, this operation should be
495 repeated 2-3 times on an otherwise inactive system (no other
496 active processes) with at least a couple of megabytes of free
497 memory. This displays the speed of reading through the buffer
498 cache to the disk without any prior caching of data. This mea‐
499 surement is an indication of how fast the drive can sustain
500 sequential data reads under Linux, without any filesystem over‐
501 head. To ensure accurate measurements, the buffer cache is
502 flushed during the processing of -t using the BLKFLSBUF ioctl.
503 -T Perform timings of cache reads for benchmark and comparison pur‐
505 poses. For meaningful results, this operation should be
506 repeated 2-3 times on an otherwise inactive system (no other
507 active processes) with at least a couple of megabytes of free
508 memory. This displays the speed of reading directly from the
509 Linux buffer cache without disk access. This measurement is
510 essentially an indication of the throughput of the processor,
511 cache, and memory of the system under test.
512 --trim-sector-ranges
514 For Solid State Drives (SSDs). EXCEPTIONALLY DANGEROUS. DO NOT
515 USE THIS OPTION!! Tells the drive firmware to discard unneeded
516 data sectors, destroying any data that may have been present
517 within them. This makes those sectors available for immediate
518 use by the firmware's garbage collection mechanism, to improve
519 scheduling for wear-leveling of the flash media. This option
520 expects one or more sector range pairs immediately after the
521 option: an LBA starting address, a colon, and a sector count
522 (max 65535), with no intervening spaces. EXCEPTIONALLY DANGER‐
523 OUS. DO NOT USE THIS OPTION!!
524 E.g. hdparm --trim-sector-ranges 1000:4 7894:16 /dev/sdz
526 --trim-sector-ranges-stdin
528 Identical to --trim-sector-ranges above, except the list of
529 lba:count pairs is read from stdin rather than being specified
530 on the command line. This can be used to avoid problems with
531 excessively long command lines. It also permits batching of
532 many more sector ranges into single commands to the drive, up to
533 the currently configured transfer limit (max_sectors_kb).
534 -u Get/set the interrupt-unmask flag for the drive. A setting of 1
536 permits the driver to unmask other interrupts during processing
537 of a disk interrupt, which greatly improves Linux´s responsive‐
538 ness and eliminates "serial port overrun" errors. Use this fea‐
539 ture with caution: some drive/controller combinations do not
540 tolerate the increased I/O latencies possible when this feature
541 is enabled, resulting in massive filesystem corruption. In par‐
542 ticular, CMD-640B and RZ1000 (E)IDE interfaces can be unreliable
543 (due to a hardware flaw) when this option is used with kernel
544 versions earlier than 2.0.13. Disabling the IDE prefetch fea‐
545 ture of these interfaces (usually a BIOS/CMOS setting) provides
546 a safe fix for the problem for use with earlier kernels.
547 -v Display some basic settings, similar to -acdgkmur for IDE. This
549 is also the default behaviour when no options are specified.
550 -V Display program version and exit immediately.
552 --verbose
554 Display extra diagnostics from some commands.
555 -w Perform a device reset (DANGEROUS). Do NOT use this option. It
557 exists for unlikely situations where a reboot might otherwise be
558 required to get a confused drive back into a useable state.
559 --write-sector
561 Writes zeros to the specified sector number. VERY DANGEROUS.
562 The sector number must be given (base10) after this option.
563 hdparm will issue a low-level write (completely bypassing the
564 usual block layer read/write mechanisms) to the specified sec‐
565 tor. This can be used to force a drive to repair a bad sector
566 (media error).
567 -W Get/set the IDE/SATA drive´s write-caching feature.
569 -X Set the IDE transfer mode for (E)IDE/ATA drives. This is typi‐
571 cally used in combination with -d1 when enabling DMA to/from a
572 drive on a supported interface chipset, where -X mdma2 is used
573 to select multiword DMA mode2 transfers and -X sdma1 is used to
574 select simple mode 1 DMA transfers. With systems which support
575 UltraDMA burst timings, -X udma2 is used to select UltraDMA
576 mode2 transfers (you´ll need to prepare the chipset for UltraDMA
577 beforehand). Apart from that, use of this option is seldom nec‐
578 essary since most/all modern IDE drives default to their fastest
579 PIO transfer mode at power-on. Fiddling with this can be both
580 needless and risky. On drives which support alternate transfer
581 modes, -X can be used to switch the mode of the drive only.
582 Prior to changing the transfer mode, the IDE interface should be
583 jumpered or programmed (see -p option) for the new mode setting
584 to prevent loss and/or corruption of data. Use this with
585 extreme caution! For the PIO (Programmed Input/Output) transfer
586 modes used by Linux, this value is simply the desired PIO mode
587 number plus 8. Thus, a value of 09 sets PIO mode1, 10 enables
588 PIO mode2, and 11 selects PIO mode3. Setting 00 restores the
589 drive´s "default" PIO mode, and 01 disables IORDY. For multi‐
590 word DMA, the value used is the desired DMA mode number plus 32.
591 for UltraDMA, the value is the desired UltraDMA mode number plus
592 64.
593 -y Force an IDE drive to immediately enter the low power consump‐
595 tion standby mode, usually causing it to spin down. The current
596 power mode status can be checked using the -C option.
597 -Y Force an IDE drive to immediately enter the lowest power con‐
599 sumption sleep mode, causing it to shut down completely. A hard
600 or soft reset is required before the drive can be accessed again
601 (the Linux IDE driver will automatically handle issuing a reset
602 if/when needed). The current power mode status can be checked
603 using the -C option.
604 -z Force a kernel re-read of the partition table of the specified
606 device(s).
607 -Z Disable the automatic power-saving function of certain Seagate
609 drives (ST3xxx models?), to prevent them from idling/spinning-
610 down at inconvenient times.
611 ATA Security Feature Set
614 These switches are DANGEROUS to experiment with, and might not work
616 with some kernels. USE AT YOUR OWN RISK.
617 --security-help
619 Display terse usage info for all of the --security-* options.
620 --security-freeze
622 Freeze the drive´s security settings. The drive does not accept
623 any security commands until next power-on reset. Use this func‐
624 tion in combination with --security-unlock to protect drive from
625 any attempt to set a new password. Can be used standalone, too.
626 No other options are permitted on the command line with this
627 one.
628 --security-prompt-for-password
630 Prompt for the --security PWD rather than getting from the com‐
631 mand line args. This avoids having passwords show up in shell
632 history or in /proc/self/cmdline during execution.
633 --security-unlock PWD
635 Unlock the drive, using password PWD. Password is given as an
636 ASCII string and is padded with NULs to reach 32 bytes. The
637 applicable drive password is selected with the --user-master
638 switch (default is "user" password). No other options are per‐
639 mitted on the command line with this one.
640 --security-set-pass PWD
642 Lock the drive, using password PWD (Set Password) (DANGEROUS).
643 Password is given as an ASCII string and is padded with NULs to
644 reach 32 bytes. Use the special password NULL to set an empty
645 password. The applicable drive password is selected with the
646 --user-master switch (default is "user" password) and the appli‐
647 cable security mode with the --security-mode switch. No other
648 options are permitted on the command line with this one.
649 --security-disable PWD
651 Disable drive locking, using password PWD. Password is given as
652 an ASCII string and is padded with NULs to reach 32 bytes. The
653 applicable drive password is selected with the --user-master
654 switch (default is "user" password). No other options are per‐
655 mitted on the command line with this one.
656 --security-erase PWD
658 Erase (locked) drive, using password PWD (DANGEROUS). Password
659 is given as an ASCII string and is padded with NULs to reach 32
660 bytes. Use the special password NULL to represent an empty
661 password. The applicable drive password is selected with the
662 --user-master switch (default is "user" password). No other
663 options are permitted on the command line with this one.
664 --security-erase-enhanced PWD
666 Enhanced erase (locked) drive, using password PWD (DANGEROUS).
667 Password is given as an ASCII string and is padded with NULs to
668 reach 32 bytes. The applicable drive password is selected with
669 the --user-master switch (default is "user" password). No other
670 options are permitted on the command line with this one.
671 --user-master USER
673 Specifies which password (user/master) to select. Defaults to
674 user password. Only useful in combination with --security-
675 unlock, --security-set-pass, --security-disable, --security-
676 erase or --security-erase-enhanced.
677 u user password
678 m master password
679 --security-mode MODE
682 Specifies which security mode (high/maximum) to set. Defaults
683 to high. Only useful in combination with --security-set-pass.
684 h high security
685 m maximum security
686 THIS FEATURE IS EXPERIMENTAL AND NOT WELL TESTED. USE AT YOUR
688 OWN RISK.
689
691 /etc/hdparm.conf
692
694 As noted above, the -m sectcount and -u 1 options should be used with
695 caution at first, preferably on a read-only filesystem. Most drives
696 work well with these features, but a few drive/controller combinations
697 are not 100% compatible. Filesystem corruption may result. Backup
698 everything before experimenting!
699 Some options (e.g. -r for SCSI) may not work with old kernels as neces‐
701 sary ioctl()´s were not supported.
702 Although this utility is intended primarily for use with SATA/IDE hard
704 disk devices, several of the options are also valid (and permitted) for
705 use with SCSI hard disk devices and MFM/RLL hard disks with XT inter‐
706 faces.
707 The Linux kernel up until 2.6.12 (and probably later) doesn´t handle
709 the security unlock and disable commands gracefully and will segfault
710 and in some cases even panic. The security commands however might
711 indeed have been executed by the drive. This poor kernel behaviour
712 makes the PIO data security commands rather useless at the moment.
713 Note that the "security erase" and "security disable" commands have
715 been implemented as two consecutive PIO data commands and will not suc‐
716 ceed on a locked drive because the second command will not be issued
717 after the segfault. See the code for hints how patch it to work around
718 this problem. Despite the segfault it is often still possible to run
719 two instances of hdparm consecutively and issue the two necessary com‐
720 mands that way.
721
723 hdparm has been written by Mark Lord <mlord@pobox.com>, the original
724 primary developer and maintainer of the (E)IDE driver for Linux, and
725 current contributor to the libata subsystem, along with suggestions and
726 patches from many netfolk.
727 The disable Seagate auto-powersaving code is courtesy of Tomi Leppikan‐
729 gas(tomilepp@paju.oulu.fi).
730 Security freeze command by Benjamin Benz, 2005.
732 PIO data out security commands by Leonard den Ottolander, 2005. Some
734 other parts by Benjamin Benz and others.
735
737 http://www.t13.org/ Technical Committee T13 AT Attachment (ATA/ATAPI)
738 Interface.
739 http://www.serialata.org/ Serial ATA International Organization.
741 http://www.compactflash.org/ CompactFlash Association.
743Version 9.54 February 2018 HDPARM(8)