2008/8/26 Richard Elling <[EMAIL PROTECTED]>: > >> Doing a good job with this error is mostly about not freezing >> the whole filesystem for the 30sec it takes the drive to report the >> error. > > That is not a ZFS problem. Please file bugs in the appropriate category.
Who's problem is it? It can't be the device driver as that has no knowledge of zfs filesystems or redundancy. > >> Either the drives should be loaded with special firmware that >> returns errors earlier, or the software LVM should read redundant data >> and collect the statistic if the drive is well outside its usual >> response latency. > > ZFS will handle this case as well. How is ZFS handling this? Is there a timeout in ZFS? >> One thing other LVM's seem like they may do better >> than ZFS, based on not-quite-the-same-scenario tests, is not freeze >> filesystems unrelated to the failing drive during the 30 seconds it's >> waiting for the I/O request to return an error. >> > > This is not operating in ZFS code. In what way is freezing a ZFS filesystem not operating in ZFS code? Notice that he wrote filesystems unrelated to the failing drive. > >> In terms of FUD about ``silent corruption'', there is none of it when >> the drive clearly reports a sector is unreadable. Yes, traditional >> non-big-storage-vendor RAID5, and all software LVM's I know of except >> ZFS, depend on the drives to report unreadable sectors. And, >> generally, drives do. so let's be clear about that and not try to imply >> that the ``dominant failure mode'' causes silent corruption for >> everyone except ZFS and Netapp users---it doesn't. >> > > In my field data, the dominant failure mode for disks is unrecoverable > reads. If your software does not handle this case, then you should be > worried. We tend to recommend configuring ZFS to manage data > redundancy for this reason. He is writing that all software LVM's will handle unrecoverable reads. What is your definition of unrecoverable reads? _______________________________________________ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
