Messages in this thread | | | Date | Fri, 28 Feb 2003 09:35:28 -0500 | From | "Robert L. Harris" <> | Subject | Slowing down disk access? |
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I've got a system I need to slow down disk access on it would seem. The syerver, a dual 1.5Ghz Athalon has two 3ware IDE controllers, 8 disks each for a total of sixteen 180 Gig disks. This system is laid out in four RAID5 arrays that it shares out via NFS. kernel 2.4.19-ac4, ext3 file systems. I've got 7 of these.
This works great and provides a LOT of cheap disk that we use for staging backups before cloning off to tape.
The problem is that when the array's get pounded HARD, such as when legato is cleaning it's file devices (nsrstage -C) the machine will lock up and spew errors to my console:
3w-xxxx: scsi1: Command failed: status = 0xc7, flags = 0x1b, unit #7. 3w-xxxx: scsi1: Command failed: status = 0xc7, flags = 0x1b, unit #7. 3w-xxxx: scsi1: Command failed: status = 0xc7, flags = 0x1b, unit #7. 3w-xxxx: scsi1: Command failed: status = 0xc7, flags = 0x1b, unit #7. 3w-xxxx: scsi1: Command failed: status = 0xc7, flags = 0x1b, unit #7. 3w-xxxx: scsi1: Command failed: status = 0xc7, flags = 0x1b, unit #7. 3w-xxxx: scsi1: Command failed: status = 0xc7, flags = 0x1b, unit #7. 3w-xxxx: scsi1: Command failed: status = 0xc7, flags = 0x1b, unit #7. 3w-xxxx: scsi1: Command failed: status = 0xc7, flags = 0x1b, unit #7. 3w-xxxx: scsi1: AEN: WARNING: ATA port timeout: Port #7. 3w-xxxx: scsi1: AEN: WARNING: ATA port timeout: Port #7. 3w-xxxx: scsi1: AEN: WARNING: ATA port timeout: Port #7. 3w-xxxx: scsi1: AEN: WARNING: ATA port timeout: Port #7. 3w-xxxx: scsi1: AEN: WARNING: ATA port timeout: Port #7. 3w-xxxx: scsi1: AEN: WARNING: ATA port timeout: Port #7. 3w-xxxx: scsi1: AEN: WARNING: ATA port timeout: Port #7. 3w-xxxx: scsi1: AEN: WARNING: ATA port timeout: Port #7.
This requires a hard reboot. If I use the magic keys and reset it then it goes down but doesn't come back up properly, usually dieing around the LILO area, I believe the array or disks are left in an odd state.
Is there a way to actually slow down the disk access/read/write other than re-making the filesystems? On the other systems the chunk size is at either 32K or 128K. On this one in particular the chunk size is 1024K which was determined by running a number of tests (bonnie, nfs reads/writes) and was found to be about the fastest for our money's worth. The disk hangups didn't appear until just recently. If there's no other choise I can leave the disks as read only until the data rolls off then remake them in 32 or 64K.
Any other thoughts? Robert
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