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correlator:loaddisks

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How to load XRAID disk sets

  • Ensure no one is using the disks: lsof in the directories where the data is
  • Disable NFS on the computer to which the destination xraid is attached - I don't know how to do this safely yet
  • Unmount the disks: sudo umount /exports/xraid/*
  • Go to the cluster room. Power down the xraid (this can be done in software from the comfort of your office through “XRAID admin tools”, which isn't yet installed).
  • Remove disks and replace in appropriate cases in order!
  • Insert new disks, #1 on the left, #7 on the right. Check contacts on disks (and in XRAID if possible) before inserting into XRAID chassis. Disks slide in and then require a final push, you should hear them lock (thump!) into place, at which stage with the handle depressed they will be flush with the chassis.
  • Power on XRAID. This should be done in the cluster room so you can watch for alarms/red lights. The power button is on the BACK of the chassis.
  • If all disks come up green, you can go back to your office! Otherwise, open XRAID admin tools and rebuild the disk set. See Rebuilding XRAIDs.
  • If the cuppa machine was NOT powered down (shouldn't need to be), run udevtrigger
  • Trust the system! Mount devices using sudo mount /exports/xraid/?_? where ?_? is l_1, l_2, l_3, r_1, r_2, r_3 as required (left and right referring to disk banks in a chassis). We believe that this will mount the first left device in l_1 and so forth. However you should check this by ensuring that the data you expect to be on the device is in fact there before you try doing anything with it! ABSOLUTELY NO WARRANTY and all that. If you're concerned, then mount them manually in the cluster room, mounting /dev/sd?1 to the exports directory you want it to be, and making sure the left/right set of lights come on when you run the command. I believe devices always come up in the same order within a disk set, but disk sets are not always recognised in the same order (left-right, right-left, alternating) in a chassis.

NOTE At this time, this will make the devices be mounted locally on the cuppa machine attached to the xraid - ie xraid01 is on cuppa01, xraid05 is on cuppa05.

NFS mounting

  • It is now possible to mount the Xraids over nfs as any user, with e.g. mount /nfs/xraid01/l_1. To make life easier, there are shell scripts to do it in /home/corr/LBA/scripts/ mountxraids.sh and unmountxraids.sh
  • On cuppa01, type cssh cuppa to get a multi-window command prompt, so the scripts can be run simultaneously on all cuppas.
  • To change disks, after unmounting from NFS, it seems to be necessary to restart the nfs server on the local host node: sudo /etc/initd/nfs-kernel-server restart in order to umount /exports/xraid01/l_1 etc. without getting “device busy” errors. Be a bit careful doing this… try to check that noone is running stuff first. If other people are logged on may get stale file handle problems.


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correlator/loaddisks.1226021757.txt.gz · Last modified: 2008/11/07 12:35 by chotan