Re: Bug with RAID1 hot spares?
Chase Venters wrote: Greetings, I was just testing a server I was about to send into production on kernel 2.6.18.1. The server has three SCSI disks with md1 set to a RAID1 with 2 mirrors and 1 spare. I have to ask, why? If the array is mostly written you might save a bit of bus time, but for reads having another copy of the data to read (usually) helps the performance by reducing wait for read occurences. -- bill davidsen [EMAIL PROTECTED] CTO TMR Associates, Inc Doing interesting things with small computers since 1979 - To unsubscribe from this list: send the line unsubscribe linux-raid in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html
Re: Bug with RAID1 hot spares?
On Tuesday 24 October 2006 20:41, Bill Davidsen wrote: Chase Venters wrote: Greetings, I was just testing a server I was about to send into production on kernel 2.6.18.1. The server has three SCSI disks with md1 set to a RAID1 with 2 mirrors and 1 spare. I have to ask, why? If the array is mostly written you might save a bit of bus time, but for reads having another copy of the data to read (usually) helps the performance by reducing wait for read occurences. The main idea is to not exercise the spare as much as the other disks. All three disks are from the same lot. Having three disks fail at once is admittedly unlikely, but keeping one disk as a spare rather than full mirror should probably reduce the wear on that disk so if there is some manufacturing defect the third drive wouldn't be as close to failing and could hopefully keep the box online until someone makes it to the datacenter to do a swap. Thanks, Chase - To unsubscribe from this list: send the line unsubscribe linux-raid in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html
Re: Bug with RAID1 hot spares?
On Friday October 20, [EMAIL PROTECTED] wrote: Greetings, I was just testing a server I was about to send into production on kernel 2.6.18.1. The server has three SCSI disks with md1 set to a RAID1 with 2 mirrors and 1 spare. The mirrors are sda3 and sdb3, spare is sdc3. I manually failed sdb3, and as expected, sdc3 was activated. Strangely enough, /proc/mdstat did not indicate that sdc3 was being synced. I thought these spares weren't kept mirrored until needed? Correct. They are not kept mirrored. So there's definitely something odd happening here... why did no resync to the sdc3 spare start when I failed sdb3? yes... can you check that this fixes it please? Thanks, NeilBrown Signed-off-by: Neil Brown [EMAIL PROTECTED] ### Diffstat output ./drivers/md/md.c |1 + 1 file changed, 1 insertion(+) diff .prev/drivers/md/md.c ./drivers/md/md.c --- .prev/drivers/md/md.c 2006-10-23 12:09:08.0 +1000 +++ ./drivers/md/md.c 2006-10-23 14:10:46.0 +1000 @@ -2003,6 +2003,7 @@ static mdk_rdev_t *md_import_device(dev_ kobject_init(rdev-kobj); rdev-desc_nr = -1; + rdev-saved_raid_disk = -1; rdev-flags = 0; rdev-data_offset = 0; rdev-sb_events = 0; - To unsubscribe from this list: send the line unsubscribe linux-raid in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html
