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Seagate - SMART Raw Read Error Rate test
I've been trying to make sense of the SMART Raw Read Error Rate
attribute reported by my Seagate drive, model ST3120026A. To this end I have conducted an experiment where I've booted to a FreeDOS diskette which creates a RAM drive containing the following programs: debug.exe (from MS-DOS) smartudm.exe (a DOS SMART utility) http://www.sysinfolab.com/files/smartudm.zip (37KB) I have used Smartudm to record the values of the HDD's SMART attributes before and after each operation. To establish a baseline, I have executed the following commands: smartudm 0 /r before.rpt smartudm 0 /r after.rpt The before and after reports show that the Seek Error Rate (SER) increases by 8 counts and the Raw Read Error Rate (RRER) increases by 3. This appears to be the overhead for Smartudm. The following commands also produce the same result: smartudm 0 /r before.rpt debug -q smartudm 0 /r after.rpt I now use Debug to read a certain number of sectors from the C: drive (HDD) as follows: debug -L 100 2 0 nnn (where nnn = number of sectors in hex) -Q The following table shows how the values for SER and RRER are affected: Sectors SER RRER ------------------------------------------ 0x001 +9 (+1) +0x341 (+0x33E) 0x200 +9 (+1) +0x341 (+0x33E) 0x210 +9 (+1) +0x342 (+0x33F) +0x001 0x280 +9 (+1) +0x3B2 (+0x3AF) +0x070 0x300 +9 (+1) +0x432 (+0x42F) +0x080 0x400 +10 (+2) +0x532 (+0x52F) +0x100 The figures in brackets are adjusted to account for Smartudm's overhead. The last column indicates the increase in the RRER count. It appears that the HDD reads a minimum of 0x33E (=830) sectors, after which each increment in the RRER value corresponds to one additional sector. AFAICT, the HDD always reads 0x132 sectors more than requested, which probably corresponds to a look-ahead buffer of around 150KB. - Franc Zabkar -- Please remove one 'i' from my address when replying by email. |
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Seagate - SMART Raw Read Error Rate test
On Wed, 28 Jan 2009 17:49:40 +1100, Franc Zabkar
put finger to keyboard and composed: To establish a baseline, I have executed the following commands: smartudm 0 /r before.rpt smartudm 0 /r after.rpt The before and after reports show that the Seek Error Rate (SER) increases by 8 counts and the Raw Read Error Rate (RRER) increases by 3. This appears to be the overhead for Smartudm. Why do 8 seeks result in only 3 reads? I now use Debug to read a certain number of sectors from the C: drive (HDD) ... The following table shows how the values for SER and RRER are affected: Sectors SER RRER ------------------------------------------ 0x001 +9 (+1) +0x341 (+0x33E) 0x200 +9 (+1) +0x341 (+0x33E) 0x210 +9 (+1) +0x342 (+0x33F) +0x001 0x280 +9 (+1) +0x3B2 (+0x3AF) +0x070 0x300 +9 (+1) +0x432 (+0x42F) +0x080 0x400 +10 (+2) +0x532 (+0x52F) +0x100 The figures in brackets are adjusted to account for Smartudm's overhead. The last column indicates the increase in the RRER count. It appears that the HDD reads a minimum of 0x33E (=830) sectors, after which each increment in the RRER value corresponds to one additional sector. AFAICT, the HDD always reads 0x132 sectors more than requested, which probably corresponds to a look-ahead buffer of around 150KB. It would appear that the drive doesn't cache reads. For example, I would have thought that when reading 0x400 sectors, the first 0x300 sectors could be fetched from the drive's read cache. Is this behaviour by design, or does the read cache need to be explicitly enabled? Does Seagate expect the OS to handle read caching rather than the drive? BTW, I am aware that the drive's write caching can be enabled or disabled. - Franc Zabkar -- Please remove one 'i' from my address when replying by email. |
#3
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Seagate - SMART Raw Read Error Rate test
On Wed, 28 Jan 2009 17:49:40 +1100, Franc Zabkar
put finger to keyboard and composed: I've been trying to make sense of the SMART Raw Read Error Rate attribute reported by my Seagate drive, model ST3120026A. I know it's bad practice to reply to one's own posts, but here is an illuminating message from Seagate's forums: http://forums.seagate.com/stx/board/....id=8843#M8843 The OP states that the Raw Read Error Rate counts to 250,000,000 and then switches back to 0. I suspect that the lower 28 bits may reflect a sector count, allowing for 268,435,456 reads. The uppermost bits may hold an error count. The cycle is probably repeated for the next block of 256M reads, and the normalised value is probably incremented or decremented depending on the new error count. - Franc Zabkar -- Please remove one 'i' from my address when replying by email. |
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Seagate - SMART Raw Read Error Rate test
On Tue, 03 Feb 2009 06:56:35 +1100, Franc Zabkar wrote:
On Wed, 28 Jan 2009 17:49:40 +1100, Franc Zabkar put finger to keyboard and composed: I've been trying to make sense of the SMART Raw Read Error Rate attribute reported by my Seagate drive, model ST3120026A. I know it's bad practice to reply to one's own posts, but here is an Nah, reply to any post you feel like Interesting thread, I've got a 'bad' 250GB drive that has a huge seek error rate, right from day one, yet it passes the Seagate warranty return test. Had it for a few years now, never lost data, though it is slower on test than a similar 250GB drive. The processed numbers? Worst 38, curently 53 (report threshold is 30). I checked five more Seagates, from 80GB to 500GB, the 80GB had 5 in the top 16bits raw value (currently 87), but it's been running over 20000 hours, the rest of the drives have zero on the top 16bits. Grant. -- http://bugsplatter.id.au |
#5
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Seagate - SMART Raw Read Error Rate test
On Tue, 03 Feb 2009 11:54:44 +1100, Grant
put finger to keyboard and composed: On Tue, 03 Feb 2009 06:56:35 +1100, Franc Zabkar wrote: On Wed, 28 Jan 2009 17:49:40 +1100, Franc Zabkar put finger to keyboard and composed: I've been trying to make sense of the SMART Raw Read Error Rate attribute reported by my Seagate drive, model ST3120026A. I know it's bad practice to reply to one's own posts, but here is an Nah, reply to any post you feel like Interesting thread, I've got a 'bad' 250GB drive that has a huge seek error rate, right from day one, yet it passes the Seagate warranty return test. Had it for a few years now, never lost data, though it is slower on test than a similar 250GB drive. The processed numbers? Worst 38, curently 53 (report threshold is 30). I checked five more Seagates, from 80GB to 500GB, the 80GB had 5 in the top 16bits raw value (currently 87), but it's been running over 20000 hours, the rest of the drives have zero on the top 16bits. Grant. I repeated my Debug/Smartudm test for a 20GB Fujitsu MPF3024AT HDD. Sectors SER RRER ---------------------------------- 0x001 +1 +0x1DE 0x200 +0x3DD +0x1FF 0x300 +0x4DD +0x100 0x400 +3 +0x5DD +0x100 It appears that Fujitsu also counts reads and seeks in the lower bytes of the raw attribute value. The look-ahead read buffer appears to be 0x1DD sectors, ie 244KB, and the read cache appears to be disabled. Fujitsu differs from Seagate in that repeatedly retrieving SMART data does not increment the SER or RRER counts. This may be because Fujitsu does not count any SMART related disc activity toward the SMART attributes, or perhaps the SMART data are stored in EEPROM rather than on the platters. After examining more than a year of daily Fujitsu SMART reports, it appears that the maximum raw values for the RRER and SER attributes are 0x3FFFF (=256K) and 0xFFF (=4K), respectively. Therefore it looks like Seagate's raw numbers are much higher than those of other manufacturers merely because Seagate uses a much larger number of counts for averaging purposes. - Franc Zabkar -- Please remove one 'i' from my address when replying by email. |
#6
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Seagate - SMART Raw Read Error Rate test
In message Grant
was claimed to have wrote: Interesting thread, I've got a 'bad' 250GB drive that has a huge seek error rate, right from day one, yet it passes the Seagate warranty return test. Had it for a few years now, never lost data, though it is slower on test than a similar 250GB drive. Why didn't you / don't you warranty it? |
#7
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Seagate - SMART Raw Read Error Rate test
On Tue, 03 Feb 2009 17:17:13 -0800, DevilsPGD wrote:
In message Grant was claimed to have wrote: Interesting thread, I've got a 'bad' 250GB drive that has a huge seek error rate, right from day one, yet it passes the Seagate warranty return test. Had it for a few years now, never lost data, though it is slower on test than a similar 250GB drive. Why didn't you / don't you warranty it? You cannot read? Drive passes the Seagate RMA warranty test. Grant. -- http://bugsplatter.id.au |
#8
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Seagate - SMART Raw Read Error Rate test
In message Grant
was claimed to have wrote: On Tue, 03 Feb 2009 17:17:13 -0800, DevilsPGD wrote: In message Grant was claimed to have wrote: Interesting thread, I've got a 'bad' 250GB drive that has a huge seek error rate, right from day one, yet it passes the Seagate warranty return test. Had it for a few years now, never lost data, though it is slower on test than a similar 250GB drive. Why didn't you / don't you warranty it? You cannot read? Drive passes the Seagate RMA warranty test. Unimportant, if you're seeing huge seek error rates, or significantly slower performance then matching (model+firmware) drives, Seagate absolutely will accept the RMA request. A failure in SeaTools is one reason to send in an RMA request, but it's not the only reason that will be accepted. |
#9
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Seagate - SMART Raw Read Error Rate test
On Wed, 04 Feb 2009 09:07:33 -0800, DevilsPGD
put finger to keyboard and composed: In message Grant was claimed to have wrote: On Tue, 03 Feb 2009 17:17:13 -0800, DevilsPGD wrote: In message Grant was claimed to have wrote: Interesting thread, I've got a 'bad' 250GB drive that has a huge seek error rate, right from day one, yet it passes the Seagate warranty return test. Had it for a few years now, never lost data, though it is slower on test than a similar 250GB drive. Why didn't you / don't you warranty it? You cannot read? Drive passes the Seagate RMA warranty test. Unimportant, if you're seeing huge seek error rates, or significantly slower performance then matching (model+firmware) drives, Seagate absolutely will accept the RMA request. AFAICT, huge raw values for Seagate's Seek Error Rate SMART attribute are nearly always a very good sign. For example, these are the data for my 120GB ST3120026A HDD: http://www.users.on.net/~fzabkar/SmartUDM/120GB.RPT Attribute ID Threshold Value Worst Raw ---------------------------------------------------------------- Seek Error Rate 7 30 79 60 00000580A6ACh The seek error rate appears to be 0 errors in 92 million seeks. If by "huge seek error rate" you mean low numbers for the normalised value, then that's a different matter ... - Franc Zabkar -- Please remove one 'i' from my address when replying by email. |
#10
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Seagate - SMART Raw Read Error Rate test
Previously DevilsPGD wrote:
In message Grant was claimed to have wrote: On Tue, 03 Feb 2009 17:17:13 -0800, DevilsPGD wrote: In message Grant was claimed to have wrote: Interesting thread, I've got a 'bad' 250GB drive that has a huge seek error rate, right from day one, yet it passes the Seagate warranty return test. Had it for a few years now, never lost data, though it is slower on test than a similar 250GB drive. Why didn't you / don't you warranty it? You cannot read? Drive passes the Seagate RMA warranty test. Unimportant, if you're seeing huge seek error rates, or significantly slower performance then matching (model+firmware) drives, Seagate absolutely will accept the RMA request. A failure in SeaTools is one reason to send in an RMA request, but it's not the only reason that will be accepted. Seagate sasys somnething different on their website, but it is possible to trick them by claiming Seatools would not even run and get an RMA number that way. As drives are very likely not tested when they are received on an RMA, you will get a replacement anyways. I have used this approach for Seagate and Maxtor sucessfully on not-quite-deat-yet drives. So, while a huge raw seek error rate may not mean anything, you will very likely get a replacemen even for a drive that is completely fine. Significantly slower performance, however, is a clear warning sign. Of course you need to measure this without filesystem, as the filesystem can also cause slowdowns in disks that are fine. Arnio |
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