raid5 + smartctl + uncorrectable read error + single-block-resync ?
I've got smartd running (great tool: http://smartmontools.sf.net) and it just alerted me to an unreadable sector in one drive on a software raid5 array I have (linux kernel 2.4.18, I believe, I know its old)
smartctl is capable of telling me exactly what LBA on the drive is unreadable, and I was reading this, which indicates it would be possible to remap that single block:
http://cgi.cse.unsw.edu.au/~neilb/me/SoftRaid/01084418693
...but I'm guessing that's just an idea, since its from May 13th 2004 and there a couple of indications of kernel hacking in it ("maintain a list of bad blocks", check thresholds, work on the recovery thread, etc)
Is there any motion to get raid to implement this?
If there is, I guess my only input (I'm a sysadmin level hacker, not a kernel hacker) would be to say - there should be some interface for external utilities to "educate" the linux raid module that a specific disk has a specific sector going bad.
That way you could script smartd to take the results of a failed offline SMART test and send the bad LBAs to the raid module for read tests and resync
Oh, and I want a pony. ;-) I couldn't resist asking that, since this is basically a gigantic feature request
In the meantime, I guess logically failing the drive and re-adding it is the only way to remap the sectors, right?
-Mike
You got it! A write to the bad sector should cause the drive to re-map the bad sector. Not all drives do this. My drives (ST118202LC with EMC firmware B801) required me to change an option in the firmware to allow this to occur.
I wish md could do this automatically! It would save a lot of down time.
Guy
-----Original Message-----
From: [email protected] [mailto:[email protected]] On Behalf Of Michael Hardy
Sent: Thursday, June 03, 2004 3:34 PM
To: [email protected]
Subject: raid5 + smartctl + uncorrectable read error + single-block-resync ?
I've got smartd running (great tool: http://smartmontools.sf.net) and it just alerted me to an unreadable sector in one drive on a software raid5 array I have (linux kernel 2.4.18, I believe, I know its old)
smartctl is capable of telling me exactly what LBA on the drive is unreadable, and I was reading this, which indicates it would be possible to remap that single block:
http://cgi.cse.unsw.edu.au/~neilb/me/SoftRaid/01084418693
...but I'm guessing that's just an idea, since its from May 13th 2004 and there a couple of indications of kernel hacking in it ("maintain a list of bad blocks", check thresholds, work on the recovery thread, etc)
Is there any motion to get raid to implement this?
If there is, I guess my only input (I'm a sysadmin level hacker, not a kernel hacker) would be to say - there should be some interface for external utilities to "educate" the linux raid module that a specific disk has a specific sector going bad.
That way you could script smartd to take the results of a failed offline SMART test and send the bad LBAs to the raid module for read tests and resync
Oh, and I want a pony. ;-) I couldn't resist asking that, since this is basically a gigantic feature request
In the meantime, I guess logically failing the drive and re-adding it is the only way to remap the sectors, right?
-Mike
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