RedHat 9 aacraid - system fails under extreme disk IO -Reproducable test case

Thomas Petersen tomp at securityminded.net
Wed Oct 8 06:42:00 CDT 2003


Hello DELL -- are you seeing this?  Your Linux customers are unhappy with
your service and support!

After thinking on this some more I've come to realize what is even more
troubling for me is the recent purchase (within the last couple of months)
of two (2) Dell PE 2650's that were shipped to me with these known problems.
Making an informed decision to purchase a 2650 (with the RH OS) that has
these known problem(s) is one thing.   

This leads me to believe I am going to have to scrutinize new purchases even
more so to ensure no known compatibility issues (Something I really
shouldn't have to spend much time on as the server -is- certified with the
RH OS).

Thomas Petersen
::: SecurityMinded Technologies :::



>>-----Original Message-----
>>From: Stefano Turolla [mailto:sturolla at eso.org] 
>>Sent: Wednesday, October 08, 2003 6:55 AM
>>To: linux-poweredge at dell.com
>>Subject: RE: RedHat 9 aacraid - system fails under extreme 
>>disk IO -Reproducable test case
>>
>>
>>Tom i completely agree with you,
>>we tried to involve DELL several times and after talking to 
>>at least 4 different people starting again to explain what 
>>the problem was, the final answer i got from the 'responsible 
>>for System Consulting within Dell Computer Germany' was 
>>
>>"Dear Mr. Turolla,
>>
>>i just got the Information from RedHat, that the best 
>>solution is to upgrade to RHEL-version, because there is more 
>>intensive support for this version. Would this be a possible 
>>solution for you ?
>>
>>Rgds
>>Markus Wammel"
>>
>>I don't think this is a solution we can accept for a machine 
>>the DELL certified to work under Linux, and we also have the 
>>same problem with 1650's, so ia m pretty sure the problem is 
>>the the interaction between aacraid driver and the PERC 3Di 
>>raid controller 
>>
>>There is also a bugzilla bug still open and it is a bit scaring 
>>reading comment from Alan Cox telling that there is some patch but no 
>>solution. https://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=92129
>>
>>
>>I think DELL should solve the problem (ongoing since at least 
>>4 months) even if the driver is developed by RedHat and 
>>Adaptec. I don't think we'll buy other DELL servers if the 
>>won't solve the problem.
>>
>>ciao
>>stefano 
>>
>>On Wed, 2003-10-08 at 02:51, Thomas Petersen wrote:
>>> I am pretty disappointed in Dell for failing to follow up 
>>on this and 
>>> resolve the issue once and for all.  This is not a new 
>>problem but it 
>>> is Dell's responsibility to rectify it as they -certify- 
>>Redhat on the 
>>> 2650 -- regardless if it's a hardware or software issue Dell is 
>>> responsible to their customers.
>>> 
>>> If this was an issue on the Microsoft platform you can bet 
>>Dell would 
>>> of worked with Microsoft and issued a patch/update long before it 
>>> became a wide spread problem.  I have always been a huge 
>>fan of Dell 
>>> equipment but their failure in this instance to support 
>>what they sell 
>>> is very troubling.
>>> 
>>> Don't get me wrong I will probably purchase Dell servers 
>>again in the 
>>> future (though not the 2650) but can anyone name one 
>>problem affecting 
>>> the Microsoft platform, related to Dell hardware and had a 
>>problem of 
>>> this magnitude, that went unresolved for as long as this one has?  
>>> System lockups are -totally- unacceptable.
>>> 
>>> I guess when people start choosing with their checkbooks Dell might 
>>> wake up.
>>> 
>>> Thomas Petersen
>>> SecurityMinded Technologies
>>> 
>>> >>-----Original Message-----
>>> >>From: Andrew Mann [mailto:amann at mythicentertainment.com]
>>> >>Sent: Tuesday, October 07, 2003 6:20 PM
>>> >>To: linux-poweredge at dell.com
>>> >>Cc: mark_salyzyn at adaptec.com
>>> >>Subject: Re: RedHat 9 aacraid - system fails under extreme 
>>> >>disk IO - Reproducable test case
>>> >>
>>> >>
>>> >>	Unfortunately we've got a good number of 2550s and
>>> >>2650s in use, and 
>>> >>replacing the RAID cards isn't ideal.  Mostly we don't have 
>>> >>enough load 
>>> >>to cause this problem, but every now and then we do get an 
>>> >>unexplained 
>>> >>lockup that pulls someone out of bed at 2 AM.
>>> >>	I searched back through the reports of this and found 
>>> >>some posts from 
>>> >>Mark Salyzyn referencing AAC_NUM_FIB and AAC_NUM_IO_FIB 
>>> >>settings.  The 
>>> >>last comment I see is on 9/9/2003:
>>> >>"I am suggesting that this value be (AAC_NUM_IO_FIB+64), and 
>>> >>limited to 
>>> >>below 512 (the maximum number of hardware FIBS the Firmware 
>>> >>can absorb). 
>>> >>I will begin testing the stability and side effects of 
>>this input."
>>> >>	However, I don't see any followup, nor does the latest 
>>> >>patchset to the 
>>> >>2.4 series seem to contain any modifications in this area (or 
>>> >>2.5 or 2.6 
>>> >>since June 2003).
>>> >>	Additionally, I've just rebuilt the aacraid module here 
>>> >>from the RedHat 
>>> >>SRPM of 2.4.20-20.9 with AAC_NUM_FIB=512 and 
>>> >>AAC_NUM_IO_FIB=448, rebuilt 
>>> >>the rdimage and such and got another crash within 5 minutes 
>>> >>of starting 
>>> >>the test.
>>> >>
>>> >>	I also see a note from Mark on 8/27/2003:
>>> >>-----
>>> >>There is code that does the following in the driver:
>>> >>
>>> >>	scsicmd->result = DID_OK << 16 | COMMAND_COMPLETE << 8
>>> >>| SAM_STAT_TASK_SET_FULL;
>>> >>	aac_io_done(scsicmd);
>>> >>	return -1;
>>> >>
>>> >>This is *wrong*, because the none zero return causes the
>>> >>system to hold 
>>> >>the command in the queue due to the use of the new error 
>>> >>handler, yet we 
>>> >>have also completed the command as `BUSY' *and* as a 
>>result of the 
>>> >>constraints of the aac_io_done call which relocks (on 
>>> >>io_request_lock) 
>>> >>the caller had to unlock leaving a hole that SMP machines 
>>fill. By 
>>> >>dropping the result and done calls in these situations, and 
>>> >>holding the 
>>> >>locks in the caller of such routines, I believe we will close 
>>> >>this hole.
>>> >>
>>> >>....
>>> >>
>>> >>I will report back on my tests of these changes, but will need a
>>> >>volunteer with kernel compile experience to report on the 
>>success in 
>>> >>resolving this issue in the field *please*.
>>> >>-----
>>> >>
>>> >>	I'm not familiar enough with the aacraid driver or scsi
>>> >>in general to 
>>> >>gather the code changes necessary.  There also don't 
>>appear to be any 
>>> >>followups.
>>> >>
>>> >>	Mark, do you have any updates on this?  I can make code
>>> >>changes, 
>>> >>recompile, and run a test case that reliably reveals the 
>>> >>problem here if 
>>> >>that's helpful.
>>> >>
>>> >>
>>> >>I can't see the full panic message, but the parts I can see are
>>> >>basically (copied by hand):
>>> >>
>>> >>CPU 1
>>> >>EFLAGS: 00010086
>>> >>
>>> >>EIP is at rmqueue [kernel] 0x127  (2.4.20-20.9smp)
>>> >>eax: c0343400    ebx: c03445dc    ecx: 00000000
>>> >>edx: b6d7ca63    esi: 00000000    edi: c03445d0
>>> >>ebp: 00038000    esp: ee643e80     ds: 0068
>>> >>es: 0068  ss: 0068
>>> >>
>>> >>Process dd (pid: 956, stack page = ee643000)
>>> >>
>>> >>Call trace:   wakeup_kswapd   0xfb (0xee643e90)
>>> >>               __aloc_pages_limit   0x57
>>> >>               __alloc_pages        0x101
>>> >>               generic_file_write   0x394
>>> >>               ext3_file_write      0x39
>>> >>               sys_write            0x97
>>> >>               system_call          0x33
>>> >>
>>> >>	Although aacraid isn't directly implicated here, I can
>>> >>reproduce this 
>>> >>on the 2550s and 2650s (aacraid) but not 1750s (megaraid).
>>> >>
>>> >>Andrew
>>> >>
>>> >>Paul Anderson wrote:
>>> >>
>>> >>> We had this same issue with our 2650's running AS 2.1.  
>>Don't know
>>> >>> that this is the best answer, but it is the one that worked for 
>>> >>> us...Replace the on board adapter with a PERC 3/DC 
>>(LSI) adapter.  
>>> >>> Make sure that you put it on its own bus, we used slot 
>>> >>three.  In 2 of
>>> >>> our 2650's we are even running this with the HBA's for SAN
>>> >>> connectivity.  That said, our solution is about 2 weeks 
>>> >>old, though I
>>> >>> did run similar tests on the systems after the new install
>>> >>for 8 days
>>> >>> and was unable to make them crash.
>>> >>> 
>>> >>> Paul
>>> >>> 
>>> >>> -----Original Message-----
>>> >>> From: Andrew Mann [mailto:amann at mythicentertainment.com]
>>> >>> Sent: Tuesday, October 07, 2003 12:47 PM
>>> >>> To: linux-poweredge at dell.com
>>> >>> Cc: Matt Domsch; deanna_bonds at adaptec.com; alan at redhat.com
>>> >>> Subject: RedHat 9 aacraid - system fails under extreme disk IO -
>>> >>> Reproducable test case
>>> >>> 
>>> >>> 
>>> >>> 	This has been brought up on the Dell Linux Poweredge
>>> >>list previously,
>>> >>> but it doesn't appear that a definative solution or reproducable
>>> >>> situation has been presented.  It also seems like the 
>>> >>previous reports
>>> >>> involved both heavy disk IO as well as heavy network
>>> >>traffic, and so the
>>> >>> NIC driver was suspect.
>>> >>> 	Since we have a number of 2550s and 2650s using the
>>> >>onboard PERC3/Di
>>> >>> raid controller (aacraid driver), this issue concerns us.
>>> >>> 
>>> >>> 	The following script was run with 6 instances at once
>>> >>on two 2550s
>>> >>> and
>>> >>> one 2650.
>>> >>> 
>>> >>> 2550 configuration
>>> >>> 2 x P3 1.2 Ghz  kernel: 2.4.20-20.9smp #1 SMP
>>> >>> 1GB of ram, 2GB of swap, 2 x 18 GB drives in a raid 1 
>>> >>> configuration
>>> >>> 
>>> >>> 2650 configuration
>>> >>> 2 x Xeon 2.2 Ghz   kernel: 2.4.20-20.9smp #1 SMP
>>> >>> 2GB of ram, 2GB of swap, 2 x 18 GB drives in a raid 1 
>>> >>> configuration
>>> >>> Hyperthreading enabled
>>> >>> 
>>> >>> 
>>> >>> 	The 2550s fail within 30 minutes of starting the tests
>>> >>each time
>>> >>> (tests
>>> >>> were run 6 times in a row).  The 2650 failed prior to 2.5
>>> >>days (only 1
>>> >>> test run due to duration before failure).  In some 
>>cases the 2550
>>> >>> displayed a null pointer dereference in the kernel.  
>>I'll copy down 
>>> >>> details next time I can catch it on screen.  It does not 
>>> >>get logged to
>>> >>> disk, which doesn't surprise me in this situation.  In most
>>> >>cases the
>>> >>> screen was blank (due to APM I'd guess?).
>>> >>> 	The systems still respond to pings, but do not respond
>>> >>to keyboard
>>> >>> actions and do not complete any tcp connections.  These
>>> >>systems do not
>>> >>> have a graphical desktop installed, and in fact have a
>>> >>fairly minimal
>>> >>> set of packages installed at all.
>>> >>> 	I don't know why the 2550 would consistantly fail in
>>> >>such a brief
>>> >>> period while the 2650 would take a much longer time before 
>>> >>> failure.
>>> >>> I've been running the same tests on a 1750 (PERC4/Di - 
>>> >>Megaraid based)
>>> >>> for some days now without a failure.
>>> >>> 	I plan on testing a non-SMP kernel on the 2550 next -
>>> >>not because we
>>> >>> can run things that way, but to maybe give some more clues.
>>> >>> 
>>> >>> 	The following script creates a 300 MB file, then rm's
>>> >>it, then does
>>> >>> it
>>> >>> all over again.  For my tests I ran 6 of these concurrently.  
>>> >>> Don't
>>> >>> expect the system to respond to much while these are 
>>> >>running, though I
>>> >>> was able to get decent updates from top.
>>> >>> 	Alter the script as you see fit, I'm no guru with bash
>>> >>scripting!
>>> >>> 
>>> >>> cat diskgrind.sh
>>> >>> #!/bin/sh
>>> >>> 
>>> >>> 
>>> >>> MEGS=300
>>> >>> TOTAL=0
>>> >>> 
>>> >>> while [ "1" != "0" ]; do
>>> >>>          dd ibs=1048576 count=$MEGS if=/dev/zero
>>> >>of=/test/diskgrind.$$
>>> >>> 2>&1 | cat >/dev/null
>>> >>>          rm -f /test/diskgrind.$$
>>> >>>          TOTAL=`expr $TOTAL + $MEGS`
>>> >>>          echo "[$$] Completed $TOTAL megs."
>>> >>> done
>>> >>> 
>>> >>> 
>>> >>> ./diskgrind.sh &
>>> >>> ./diskgrind.sh &
>>> >>> ./diskgrind.sh &
>>> >>> ./diskgrind.sh &
>>> >>> ./diskgrind.sh &
>>> >>> ./diskgrind.sh &
>>> >>> 
>>> >>> 
>>> >>> 
>>> >>> Andrew
>>> >>> 
>>> >>
>>> >>--
>>> >>Andrew Mann
>>> >>Systems Administrator
>>> >>Mythic Entertainment
>>> >>703-934-0446 x 224
>>> >>
>>> >>_______________________________________________
>>> >>Linux-PowerEdge mailing list
>>> >>Linux-PowerEdge at dell.com
>>> >>>>http://lists.us.dell.com/mailman/listinfo/linux->>poweredge
>>> >>
>>> >>
>>> >>Please read the FAQ at
>>> >>http://lists.us.dell.com/faq or search the list archives at 
>>> http://lists.us.dell.com/htdig/
>>> 
>>> 
>>> _______________________________________________
>>> Linux-PowerEdge mailing list
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>>-- 
>>+------+---------+--------+--------+--------+---------+-------
>>-+-------+
>>| Stefano Turolla                             Phone : +49 89 
>>32006537  |
>>| UNIX System Manager                         Fax   : +49 89 
>>32006380  |
>>| European Southern Observatory (ESO):        E-Mail: 
>>sturolla at eso.org |
>>| Karl-Schwarzschild-strasse 2 D-85748 Garching bei Muenchen  
>>         |
>>+------+---------+--------+--------+--------+---------+-------
>>-+-------+
>>Computers are like airconditioners ,
>>they stop working properly if you open WINDOWS
>>
>>
>>_______________________________________________
>>Linux-PowerEdge mailing list
>>Linux-PowerEdge at dell.com 
>>>>http://lists.us.dell.com/mailman/listinfo/linux->>poweredge
>>
>>
>>Please read the FAQ at 
>>http://lists.us.dell.com/faq or search the list archives at 
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