https://sig-io.nl/enContents © 2024 <a href="mailto:mark@sig-io.nl">Mark Janssen</a> Wed, 12 Jun 2024 13:43:17 GMTNikola (getnikola.com)http://blogs.law.harvard.edu/tech/rsshttps://sig-io.nl/posts/online-resizing-of-multipath-devices-in-linux-dm-multipath/Mark Janssen<p>Linux doesn’t automatically re-size multipath devices, so this procedure must be used to have online re-sizing of multipath. (Offline re-size is automatic, just remove the mapping and reload)</p> <ul class="simple"> <li><p>this example will use multipath device /dev/mpath/testdisk, with scsi disks /dev/sdx and /dev/sdy</p></li> <li><p>Resize the lun on the underlying storage layer (iscsi / san)</p></li> <li><p>Check which sd? devices are relevant, and re-scan these:</p> <ul> <li><p>multipath -ll testdisk</p></li> <li><p>blockdev –rereadpt /dev/sdx</p></li> <li><p>blockdev –rereadpt /dev/sdy</p></li> <li><p>blockdev –getsz /dev/sdx</p></li> <li><p>blockdev –getsz /dev/sdy</p></li> </ul> </li> <li><p>Take note of the new size returned by getsz.</p></li> <li><p>Dump the dmsetup table to a file (and a backup)</p> <ul> <li><p>dmsetup table testdisk | tee mapping.bak mapping.cur</p></li> </ul> </li> <li><p>Edit the table stored in ‘mapping.cur’</p> <ul> <li><p>vi mapping.cur, replace field 2 (size) with the new size from getsz</p></li> </ul> </li> <li><p>Suspend I/O, reread the table, and resume I/O</p> <ul> <li><p>dmsetup suspend testdisk; dmsetup reload testdisk mapping.cur; dmsetup resume testdisk</p></li> </ul> </li> <li><p>The multipath device should now be resized:</p></li> <li><p>multipath -ll</p></li> </ul> <p>You can now resize the filesystem on the multipath device, or the LVM-PV if you use LVM on the LUN.</p>dmsetupiscsilinuxlvmmultipathresizehttps://sig-io.nl/posts/online-resizing-of-multipath-devices-in-linux-dm-multipath/Thu, 07 Apr 2011 21:26:24 GMT