Due to power failure if your Citrix Xen Slave server doesn’t get back online in pool, this might help:
When the Xen environment changes the pool master, If a slave cannot reach the pool master it goes into a failed state. To change this edit pool.conf file (vi /etc/xensource/pool.conf) and changed the pool master IP address from 10.174.XX.XX to 10.174.XX.YY (to the correct new pool master address). The following identifies the changes as represented within the .conf file:
Once the change is complete, run xe-toolstack-restart. The management interfaces should be restarted and as a precaution the server restart should help. On reboot, you will be able to see the slave server joining the pool without any trouble.
Use the following command to copy the partition table from sda to sdb.
sfdisk -d /dev/sda | sfdisk -f /dev/sdb
sfdisk -d dumps the partition table on to stdout. This is being piped to sfdisk /dev/sdb with the –force to write it on /dev/sdb.
You can use dd to copy the Master Boot Record (MBR) from one device to another (or to a file). For example, copying the MBR from sda to sdb would be done with
dd if=/dev/sda of=/dev/sdb bs=512 count=1
The flags are
if, input file (either device or ordinary file)
of, output file (either device or ordinary file)
bs, block size in bytes
count, number of blocks to copy.
The MBR contains the partition table for the four primary partitions, so this solution alone will not copy the definition for the extended partitions.