[DRBD-user] Scsi timeout / sync rates / speed

Dan Didier dan at mapolce.com
Thu Sep 30 19:56:05 CEST 2004

Note: "permalinks" may not be as permanent as we would like,
direct links of old sources may well be a few messages off.


First some background on our systems.  They are both Dell 2400 with a
built in raid controller with 64megs of memory.  The OS is on a separate
mirrored RAID partition.  The data is a RAID 5 partition.  We are using
100mb Intel NICs for data sync.  Dual processor 733Mhz.  Both are
running Redhat9 kernel 2.4.20-31.9smp.  DRBD 0.7.4

I have been watching our systems and have some questions that hopefully
some of you can help with.
My first question is what is the difference between speed and K/sec.  As
you can see below the first output shows:
finish: 26:02:30 speed: 508 (1,428) K/sec, while the second shows:
finish: 1:17:08 speed: 10,632 (1,576) K/sec
The K/sec is the same but the speed is much lower.  Is this because of
disk write issues?

On my secondary box I get the follwing in my dmesg:
aacraid:ID(0:02:0) Timeout detected on cmd[0x2a]
aacraid:SCSI Channel[0]: Timeout Detected On 1 Command(s)
aacraid:ID(0:02:0) Timeout detected on cmd[0x2a]
aacraid:SCSI Channel[0]: Timeout Detected On 1 Command(s)
aacraid:ID(0:04:0) Timeout detected on cmd[0x28]
aacraid:SCSI Channel[0]: Timeout Detected On 1 Command(s)
aacraid:ID(0:03:0) Timeout detected on cmd[0x2a]
aacraid:SCSI Channel[0]: Timeout Detected On 1 Command(s)
aacraid:ID(0:04:0) Timeout detected on cmd[0x2a]
aacraid:SCSI Channel[0]: Timeout Detected On 1 Command(s)
aacraid:ID(0:02:0) Timeout detected on cmd[0x2a]
aacraid:SCSI Channel[0]: Timeout Detected On 1 Command(s)

I have two identical boxes.  I have swapped the drives out to make sure
this isn't a hardware issue.  This always occurs on the secondary which
I suppose would make sense as that is where all the writes are occuring.
I have tried limiting the sync rate to 1000K to see if that helps, and
it does not, I still get write problems.
Do you think this is a DRBD / Kernel issue?  Any suggestions on how to
resolve this issue?

Thanks,
Dan

[root at linux1 log]# cat /proc/drbd
version: 0.7.4 (api:76/proto:74)
SVN Revision: 1537M build by root at linux1.romestripsteel.local,
2004-09-24 08:16:46
 0: cs:SyncSource st:Secondary/Secondary ld:Consistent
    ns:90004 nr:0 dw:0 dr:94488 al:0 bm:4 lo:124 pe:2097 ua:1121 ap:0
        [>...................] sync'ed:  0.2% (48828/48907)M
        finish: 26:02:30 speed: 508 (1,428) K/sec

[root at linux1 log]# cat /proc/drbd
version: 0.7.4 (api:76/proto:74)
SVN Revision: 1537M build by root at linux1.romestripsteel.local,
2004-09-24 08:16:46
 0: cs:SyncSource st:Secondary/Secondary ld:Consistent
    ns:94736 nr:0 dw:0 dr:94736 al:0 bm:5 lo:0 pe:380 ua:0 ap:0
        [>...................] sync'ed:  0.2% (48816/48907)M
        finish: 1:17:08 speed: 10,632 (1,576) K/sec
[root at linux1 log]#



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