Hello, Fedorians! I asked this question over on redhat-list. (Was hoping to ask RedHat support.) But that list is something of a ghost town. Perhaps someone on fedora-list can comment of md behaviour when a drive gets pulled? I'd appreciate figuring this out. Thanks in advance. Sincerely, -danny ----- Forwarded message from Danny Howard <dannyman@xxxxxxxxxx> ----- Hello, I am evaluating RHEL, prior to purchase for a new production network. Our boxes are SuperMicro 6018HT with dual SATA drives. I like to give my system a bit of added resiliency with RAID1. These systems have pairs of SATA disks, but no hardware RAID. With FreeBSD, I can set up a gmirror and have a RAID1 system. (I have documentation on that at http://dannyman.toldme.com/2005/01/24/freebsd-howto-gmirror-system/ ) So, for Red Hat, I checked the manual, and thought I'd give the Red Hat method a shot. Here's a capture of my Disk Druid: http://www.flickr.com/photos/dannyman/61643870/ And, here's some info from the running system: [root@linux ~]# cat /etc/fstab # This file is edited by fstab-sync - see 'man fstab-sync' for details /dev/md2 / ext3 defaults 1 1 /dev/md0 /boot ext3 defaults 1 2 none /dev/pts devpts gid=5,mode=620 0 0 none /dev/shm tmpfs defaults 0 0 none /proc proc defaults 0 0 none /sys sysfs defaults 0 0 /dev/md1 swap swap defaults 0 0 /dev/hdc /media/cdrom auto pamconsole,fscontext=system_u:object_r:removable_t,exec,noauto,managed 0 0 /dev/fd0 /media/floppy auto pamconsole,fscontext=system_u:object_r:removable_t,exec,noauto,managed 0 0 [root@linux ~]# mount /dev/md2 on / type ext3 (rw) none on /proc type proc (rw) none on /sys type sysfs (rw) none on /dev/pts type devpts (rw,gid=5,mode=620) usbfs on /proc/bus/usb type usbfs (rw) /dev/md0 on /boot type ext3 (rw) none on /dev/shm type tmpfs (rw) none on /proc/sys/fs/binfmt_misc type binfmt_misc (rw) sunrpc on /var/lib/nfs/rpc_pipefs type rpc_pipefs (rw) [root@linux ~]# cat /etc/mdadm.conf # mdadm.conf written out by anaconda DEVICE partitions MAILADDR root ARRAY /dev/md2 super-minor=2 ARRAY /dev/md0 super-minor=0 ARRAY /dev/md1 super-minor=1 [root@linux ~]# cat /proc/mdstat Personalities : [raid1] md1 : active raid1 sdb2[1] sda2[0] 2032128 blocks [2/2] [UU] md2 : active raid1 sdb3[1] sda3[0] 76011456 blocks [2/2] [UU] md0 : active raid1 sdb1[1] sda1[0] 104320 blocks [2/2] [UU] unused devices: <none> Sweet! I can "fail" a disk and remove it thus: mdadm --fail /dev/md0 /dev/sdb1 mdadm --fail /dev/md1 /dev/sdb2 mdadm --fail /dev/md2 /dev/sdb3 [ ... physically remove disk, system is fine ... ] [ ... put the disk back in, system is fine ... ] mdadm --remove /dev/md0 /dev/sdb1 mdadm --add /dev/md0 /dev/sdb1 mdadm --remove /dev/md1 /dev/sdb2 mdadm --add /dev/md1 /dev/sdb2 mdadm --remove /dev/md2 /dev/sdb3 mdadm --add /dev/md2 /dev/sdb3 [ ... md2 does a rebuild, but /boot and <swap> are fine -- nice! ... ] Okay, but what if a disk fails on its own? [root@linux ~]# cat /proc/mdstat Personalities : [raid1] md1 : active raid1 sdb2[1] sda2[0] 2032128 blocks [2/2] [UU] md2 : active raid1 sdb3[1] sda3[0] 76011456 blocks [2/2] [UU] md0 : active raid1 sdb1[1] sda1[0] 104320 blocks [2/2] [UU] unused devices: <none> [ ... pull sdb ... ] [root@linux ~]# cat /proc/mdstat ata1: command 0x35 timeout, stat 0xd0 host_stat 0x61 ata1: status=0xd0 { Busy } SCSI error : <0 0 1 0> return code = 0x8000002 Current sdb: sense key Aborted Command Additional sense: Scsi parity error end_request: I/O error, dev sdb, sector 156296202 md: write_disk_sb failed for device sdb3 ATA: abnormal status 0xD0 on port 0x1F7 md: errors occurred during superblock update, repeating ATA: abnormal status 0xD0 on port 0x1F7 ATA: abnormal status 0xD0 on port 0x1F7 ata1: command 0x35 timeout, stat 0x50 host_stat 0x61 [ ... reinsert sdb ... ] Personalities : [raid1] md1 : active raid1 sdb2[1] sda2[0] 2032128 blocks [2/2] [UU] md2 : active raid1 sdb3[1] sda3[0] 76011456 blocks [2/2] [UU] md0 : active raid1 sdb1[1] sda1[0] 104320 blocks [2/2] [UU] unused devices: <none> I don't like that the system seems to choke when the disk is removed unexpectedly. Is this intended operation? Do I need to massage my SCSI subsystem a bit? What's up? :) Thanks for you time. Sincerely, -danny -- http://dannyman.toldme.com/ -- redhat-list mailing list unsubscribe mailto:redhat-list-request@xxxxxxxxxx?subject=unsubscribe https://www.redhat.com/mailman/listinfo/redhat-list ----- End forwarded message -----
