On Wed, 30 Oct 2013, Jonathan wrote:
May I enquire as to the nature of the filesystems on these VMs?
It surprises me that a sudden inability to write to the block device
beneath is causing such hassle at the FS layer, ext3 upward (as is
standard under RH) has a pretty robust journal system.
Maybe I've just been extremely lucky :)
On 30/10/13 13:05, Craig Cook wrote:
Linux has a "feature" where it flips the file system to Read-Only if it
detects a write error. I know it happens on ext4.
Some UNIX systems mark the block as bad and keep running.
Craig
In the case with a VM on a SAN, when a SAN (or staoage networking) fails - or
even just runs slowly - it can appear that the disk has completely
disappeared. So you cannot write the data to an alternative block and carry
on.
You can (and should) increase the kernel SCSI timeouts, and in the case of
VMware, the VM tools do this.
increasing the timeouts can cause problems as well, if the SAN gets slow it may
not cause your system to loose the disk, but if you have multiple disks on your
system, one of them failing can result in the system getting VERY slow as things
timeout repeatedly.
David Lang
_______________________________________________
Tech mailing list
Tech@lists.lopsa.org
https://lists.lopsa.org/cgi-bin/mailman/listinfo/tech
This list provided by the League of Professional System Administrators
http://lopsa.org/
