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correlator:loaddisks [2008/11/27 18:30]
chotan make mount points before you mount the disks
correlator:loaddisks [2014/03/26 19:31] (current)
hbignall
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 ====== How to load XRAID disk sets ====== ====== How to load XRAID disk sets ======
  
 +  * **Note:** as we seldom (never?) use NFS mounting now, it is usually OK to simply unmount the Xraids, power off, change disks, power on and mount the new disks. Otherwise, the following instructions may be useful.
   * Ensure no one has left open files on the disks: Run ''lsof'' in the directories where the data is located.   * Ensure no one has left open files on the disks: Run ''lsof'' in the directories where the data is located.
   * You may also want to see whether anyone is using the machine. Use the "w" command.   * You may also want to see whether anyone is using the machine. Use the "w" command.
-  * If necessary, disable NFS on the computer to which the destination xraid is attached. //I don't know how to do this safely on cuppa02 because it stops /nfs/apps and /home as well//+  * Disable NFS on the computer to which the destination xraid is attached (may not be necessary, but always check)The safest way to do this, especially on cuppa02 (as it also exports /home and /nfs/apps) is to edit the nfs exports table ''/etc/exports'' and comment out the xraid entries (by adding a '#' at the start of the line), then reload the nfs server (hopefully this will not cause any interruption to its operation) 
 +<code> 
 +>sudo /etc/init.d/nfs-kernel-server reload 
 +</code>
     * We don't typically use NFS to export disk data, but we can by simply editing /etc/exports.     * We don't typically use NFS to export disk data, but we can by simply editing /etc/exports.
 +    * If one of your partitions IS NFS mounted at the time, this may just produce errors. In this case you may have to manually figure out which node(s) the partition is mounted on. I don't know if there's an easy way to do this. You'll need to visit each node, check if the partition is mounted (eg ''ls /nfs/xraid0?/?_?''), and if so, unmount it (''sudo umount /nfs/xraid0?/?_?'').
   * Stop the disks and unmount the file systems.   * Stop the disks and unmount the file systems.
  
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 <code> <code>
-> sudo mount /exports/xraid/?_?+> sudo mount /exports/xraid0X/?_?
 </code>  </code> 
  
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     * 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.      * 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 are concerned, try mounting ''/dev/sd?1'' to the exports directory you want it to be, and make 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.     * If you are concerned, try mounting ''/dev/sd?1'' to the exports directory you want it to be, and make 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.
 +  * Now restart NFS if desired, by editing ''/etc/exports'' and removing the ''#'' character from the start of each xraid line, then run 
 +<code>
 +> sudo /etc/init.d/nfs-kernel-server reload
 +</code>
 +and on each node where you need to use these data, mount the device over NFS: 
 +<code>
 +> mount /nfs/xraid0?/?_?
 +</code>
 +(Note that sudo access is not required for this).
  
-====== NFS mounting ====== +**Tip:** parallel-ssh is useful for NFS mounting on multiple nodes
- +
-**Note** This is not recommended now. The correlator will start datastream processes on the correct local host node provided this is specified in the corresponding line of the machines file (this was apparently not always the case in the past). +
- +
-  * 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:  +
- +
-<code>sudo /etc/init.d/nfs-kernel-server restart</code> +
- +
-in order to  +
- +
-<code>umount /exports/xraid01/l_1</code>  +
- +
-etc. without getting "device busy" errors. Be a bit careful doing this... try to check that no one is running stuff first. If other people are logged on may get stale file handle problems. +
 \\ \\
  
 [[xraid|Back to XRAID menu]] [[xraid|Back to XRAID menu]]
  
correlator/loaddisks.1227771013.txt.gz · Last modified: 2008/11/27 18:30 by chotan