RAID

MDADM: Convert RAID5 to RAID10

 Linux, RAID  No Responses »
Sep 042016
 

Based on Changing a RAID-10 into a RAID-5

It is usually assumed that the best HDD organization on a backup server is a RAID5, since it provides a fairly good price/volume. Unfortunately, increasing of disk count affect to some RAID5 disadvantages, in particular the in reliability and recovery speed. For example if the server has RAID5 of 6 (six) SATA disk drives (even it’s reliable enough, such as WD Re), with one disk replacement, array recovery time is about 10 hours (in my case). At the recovery time reservation is absent, the load on the disks are increased, that increases the probability of failure of the remaining disks, and if all the disks have same series, the probability of another disk will deteriorate during the recovery, increase even more.
In this regard, it was decided to convert the existing disk array from RAID5 to RAID10 with the addition of two drives, that in theory should lead to increasing of server performance and improving reliability.

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XenServer with software RAID1 upgrade (6.1 to 6.2)

 VM, XenServer  5 Responses »
Aug 072013
 

Warning: all operations are carried out only with the first two RAID partitions, the third partition is not changed

Due to the fact that the standard update is a XenServer installation of the new XenServer with virtual machines preservation, with the loss of all the changes that were made manually on the server (installed software, changing / adding settings through the console, etc.), the update is the new XenServer installation and connection of the old virtual machines.

Based on: http://support.citrix.com/article/CTX120962

  1. Backup all VM, manually: 
    xe vm-export vm=vm_name filename=backup_fiule_name compress=true
...
xe pool-dump-database file-name=dump_name.dump

    or with XENBack

  2. VM metadata export 
    xe vm-export metadata=true --multiple filename=VMEXPORT

    Warning: store all files VMEXPORT… to another computer/data store/etc

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XenServer with software RAID1 installation (6.1, 6.2, 6.5)

 VM, XenServer  94 Responses »
Dec 292012
 

Compiled from: CodeAddict’s Blog and http://pastebin.com/buBHcfxU

First: Install XenServer on first disk (/dev/sda) and NOT configure any local storage.
/dev/sda should contain three partitions, verify this with:

sgdisk -p /dev/sda

In some cases XenServer doesn’t create third partition, i.e. result of this command has only two partitions and looks like:

Number Start (sector) End (sector) Size Code Name
1 2048 8388641 4.0 GiB 0700
2 8390656 16777249 4.0 GiB 0700

In this case you need to create third partition manually:

sgdisk --new=3:16779264:DISK_SIZE-34 /dev/sda
sgdisk --typecode=3:fd00

The second partition is used for backups during a XenServer upgrade. This partition won’t used in my XenServer upgrade method.
Now we are going to use /dev/sdb as the mirror disk. First clear the partition table.

sgdisk --zap-all /dev/sdb

and install a GPT table on it

sgdisk --mbrtogpt --clear /dev/sdb

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