megaraid_sas waiting for command and then offline

I have the same or a similar issue running 2.6.17 SMP x86_64 - the
megaraid_sas driver hangs waiting for commands and then the filesystem unmounts, leaving the machine in an unusable state until there is a hard reboot (the machine is responsive but any access, shell or otherwise, is impossible without the filesystem). While I do not have much debugging information available, this happens to me about once every 6-7 days in my pool of seven machines, so I can probably get debugging info. Since the disk is offline and I can't get remote console, I don't have any details except something similar to Dave Lloyd's post, below.

The only thing that the machines with these failures seem to have in common is the fact that they are almost exclusively writes - they are slave database machines with large memory and pretty much just replicate. The read/write machines seem to have less failures.

I am happy to help provide debugging information in any reasonable way. In the mean time, if there are any known suggestions or workarounds for the problem, I would be grateful for the guidance.

Here are what details on the controller. If you want additional info, let me know exactly what you need and I will do what I can to get it to you.:

Product Name : PERC 5/i Integrated
Serial No : 12345
FW Package Build: 5.0.1-0030
FW Version : 1.00.01-0088
BIOS Version : MT23
Ctrl-R Version :1.02-007

B-

Quoted 10 lines

I have the same or a similar issue running 2.6.17 SMP x86_64 - the
megaraid_sas driver hangs waiting for commands and then the filesystem unmounts, leaving the machine in an unusable state until there is a hard reboot (the machine is responsive but any access, shell or otherwise, is impossible without the filesystem). While I do not have much debugging information available, this happens to me about once every 6-7 days in my pool of seven machines, so I can probably get debugging info. Since the disk is offline and I can't get remote console, I don't have any details except something similar to Dave Lloyd's post, below.

Brett, is this still happening to you? We're seeing this very sporadically, but it does concern us. We've seen driver updates in 2.6.19 (v00.00.03.05) and a new Dell PERC 5/i firmware:

Package Version - 5.0.2-0003
Firmware Version - 1.00.01-0157
SASBIOS Version - MT23
Ctrl-R Version - 1.02-007
MPT Version - 00.06.71.00-IT

and haven't been able to reproduce it, but we can't find a test case to reliably reproduce the problem to know that anything was fixed (out of 31 identically configured Dell 2950's with the PERC 5/i RAID controller (configured with 6 300MB SAS drives in a RAID 5, most (all?) of them Maxtor Atlas 10k, not hot spare). Our 2950s do have 16GB of RAM each, so the firmware update (which mentions that it fixes DMA beyond 8GB) sounds promising, but I would think that if that was the problem we were experiencing, we would reproduce this much more often? We are certainly using the RAM for cache and memory, it's not like we've never touched beyond 8GB.

Does anyone have a test case to reproduce this problem reliably, or a detailed description of what actually happens (on low levels) when this problem occurs that can help to make a test? We are more interested in making this reproducible now than in finding a workaround... if anyone has any tips on how to make this *more* likely to happen we'd like to know (so far, I know to try to use XFS and enable ReadAhead).

We have seen this correlated with Patrol Reads going on at the same time, but aren't sure if this is a red herring, and haven't been able to force the issue to happen by enabling Patrol Reads.

We've only ever seen these on two machines - one machine reproduces the problem in a little over a week, and the other has reproduced it a small number of times. The machines that reproduce it run an experimental demo workload, but we have not found a test case so far to reproduce the problem on demand to find or verify solutions. We're currently swapping out machines to verify that there are no hardware problems, but the machines diagnose themselves cleanly, and the workload they run is different enough that something about the workload we can't yet synthesize into a test case is the problem.

Thank you!
Joe Malicki
Software Engineer
Metacarta, Inc.
email: [email protected]

Quoted 22 lines

The only thing that the machines with these failures seem to have in common is the fact that they are almost exclusively writes - they are slave database machines with large memory and pretty much just replicate. The read/write machines seem to have less failures.

I am happy to help provide debugging information in any reasonable way. In the mean time, if there are any known suggestions or workarounds for the problem, I would be grateful for the guidance.

Here are what details on the controller. If you want additional info, let me know exactly what you need and I will do what I can to get it to you.:

Product Name : PERC 5/i Integrated
Serial No : 12345
FW Package Build: 5.0.1-0030
FW Version : 1.00.01-0088
BIOS Version : MT23
Ctrl-R Version :1.02-007

B-

I am still seeing this and we have between 2 and 5 failures per week (across almost 20 machines). I am seeing it on ext3 (we migrated all of the machines from XFS) and with ReadAhead disabled.

You mention a firmware update but I don't see any new PERC 5 firmware packages on Dell's site... can you give me a pointer to the firmware update?

Also, has anybody had this problem on RHE? Dell does not support Linux unless it is RHE... I would be surprised is somehow RHE did not have this problem.

B-

Quoted 11 lines · Joe Malicki

Quoted 10 lines

I have the same or a similar issue running 2.6.17 SMP x86_64 - the
megaraid_sas driver hangs waiting for commands and then the filesystem unmounts, leaving the machine in an unusable state until there is a hard reboot (the machine is responsive but any access, shell or otherwise, is impossible without the filesystem). While I do not have much debugging information available, this happens to me about once every 6-7 days in my pool of seven machines, so I can probably get debugging info. Since the disk is offline and I can't get remote console, I don't have any details except something similar to Dave Lloyd's post, below.

Hi Brett!

Thanks for the response, hopefully we can gather enough data points to help solve the problem.

The new PERC 5/i integrated firmware dated 11/21/2006 is at:
http://support.dell.com/support/downloads/format.aspx?c=us&l=en&s=gen&SystemID=PWE_2950&os=LIN4&osl=en&deviceid=9182&typecnt=2&libid=46&releaseid=R139225&vercnt=3
PERC 5/E adapter:
http://support.dell.com/support/downloads/format.aspx?c=us&l=en&s=gen&SystemID=PWE_2950&os=LIN4&osl=en&deviceid=9181&typecnt=2&libid=46&releaseid=R139227&vercnt=2

The release notes describe very similar symptoms, but I am not ready to believe it yet as I can't reliably reproduce the problem well enough to be confident of a fix, though it sounds like you might be able to. Unfortunately we're using Debian at the moment, but if I can reproduce I can run on RHEL in a heartbeat to duplicate it for support (for now I'm trying to minimize variables).

Also, which driver version are you running? I noticed you were using some patches from Sumant Patro@LSI - is your driver identical to the one in 2.6.19? If not, what does it look like?

Have you noticed any correlations with patrol reads at the times of the failures? You can tell by running MegaCli -FwTermLog -Dsply -aALL

What hardware are you running (CPUs, RAM, disk configuration)?

Have you noticed any correlation with heavy network I/O (as well as disk I/O)? Some of our systems may have experienced this when running more network load than typical.

Thanks!
Joe

Quoted 13 lines · Brett G. Durrett

I am still seeing this and we have between 2 and 5 failures per week (across almost 20 machines). I am seeing it on ext3 (we migrated all of the machines from XFS) and with ReadAhead disabled.

You mention a firmware update but I don't see any new PERC 5 firmware packages on Dell's site... can you give me a pointer to the firmware update?

Also, has anybody had this problem on RHE? Dell does not support Linux unless it is RHE... I would be surprised is somehow RHE did not have this problem.

Quoted 19 lines

B-

Quoted 13 lines · Joe Malicki

Quoted 12 lines

I have the same or a similar issue running 2.6.17 SMP x86_64 - the
megaraid_sas driver hangs waiting for commands and then the filesystem unmounts, leaving the machine in an unusable state until there is a hard
reboot (the machine is responsive but any access, shell or otherwise, is
impossible without the filesystem). While I do not have much debugging information available, this happens to me about once every 6-7 days in my pool of seven machines, so I can probably get debugging info. Since the disk is offline and I can't get remote console, I don't have any details except something similar to Dave Lloyd's post, below.

_______________________________________________
Linux-PowerEdge mailing list [email protected]
http://lists.us.dell.com/mailman/listinfo/linux-poweredge
Please read the FAQ at http://lists.us.dell.com/faq

We've never had lockups like this but we did notice that the megaraid_sas modules defaults to a much higher commands per lun setting than the hardware seems to be able to handle. IIRC the default is 128 and we lowered it to 16 for the 5i and 32 for the 5E.

HTH,
Greg

Hi Brett!

Thanks for the response, hopefully we can gather enough data points to help solve the problem.

The new PERC 5/i integrated firmware dated 11/21/2006 is at:
http://support.dell.com/support/downloads/format.aspx?c=us&l=en&s=gen&SystemID=PWE_2950&os=LIN4&osl=en&deviceid=9182&typecnt=2&libid=46&releaseid=R139225&vercnt=3

PERC 5/E adapter: http://support.dell.com/support/downloads/format.aspx?c=us&l=en&s=gen&SystemID=PWE_2950&os=LIN4&osl=en&deviceid=9181&typecnt=2&libid=46&releaseid=R139227&vercnt=2

The release notes describe very similar symptoms, but I am not ready to believe it yet as I can't reliably reproduce the problem well enough to be confident of a fix, though it sounds like you might be able to. Unfortunately we're using Debian at the moment, but if I can reproduce I can run on RHEL in a heartbeat to duplicate it for support (for now I'm trying to minimize variables).

Also, which driver version are you running? I noticed you were using some patches from Sumant Patro@LSI - is your driver identical to the one in 2.6.19? If not, what does it look like?

Have you noticed any correlations with patrol reads at the times of the failures? You can tell by running MegaCli -FwTermLog -Dsply -aALL

What hardware are you running (CPUs, RAM, disk configuration)?

Have you noticed any correlation with heavy network I/O (as well as disk I/O)? Some of our systems may have experienced this when running more network load than typical.

Thanks!
Joe

Quoted 24 lines · Brett G. Durrett

I am still seeing this and we have between 2 and 5 failures per week (across almost 20 machines). I am seeing it on ext3 (we migrated all of the machines from XFS) and with ReadAhead disabled.

You mention a firmware update but I don't see any new PERC 5 firmware packages on Dell's site... can you give me a pointer to the firmware update?

Also, has anybody had this problem on RHE? Dell does not support Linux unless it is RHE... I would be surprised is somehow RHE did not have this problem.

B-

Quoted 11 lines · Joe Malicki

Quoted 10 lines

I have the same or a similar issue running 2.6.17 SMP x86_64 - the
megaraid_sas driver hangs waiting for commands and then the filesystem unmounts, leaving the machine in an unusable state until there is a hard reboot (the machine is responsive but any access, shell or otherwise, is impossible without the filesystem). While I do not have much debugging information available, this happens to me about once every 6-7 days in my pool of seven machines, so I can probably get debugging info. Since the disk is offline and I can't get remote console, I don't have any details except something similar to Dave Lloyd's post, below.