How to add additional disks to XenServer host

Transcription

1 How to add additional disks to XenServer host This article explains how to add physical disk drives to a XenServer host, so that more capacity is available for the XenServer guests. Create Linux LVM partition The first step is to write a new partition table on the second disk drive using the fdisk command. # fdisk /dev/sdb The number of cylinders for this disk is set to There is nothing wrong with that, but this is larger than 1024, and could in certain setups cause problems with: 1) software that runs at boot time (e.g., old versions of LILO) 2) booting and partitioning software from other OSs (e.g., DOS FDISK, OS/2 FDISK) Command (m for help): p Disk /dev/sdb: GB, bytes 255 heads, 63 sectors/track, cylinders Units = cylinders of * 512 = bytes Device Boot Start End Blocks Id System /dev/sdb e Linux LVM Add new disk to XenServer LVM The next step is to make the new disk partition known to the LVM using the pvcreate command. The pvdisplay command lists all physical volumes associated with LVM. The first physical volume is the original XenServer LVM partition on the first disk, the second entry is our new one.

2 # pvcreate /dev/sdb1 Physical volume "/dev/sdb1" successfully created # pvdisplay --- Physical volume --- PV Name /dev/sda3 VG Name VG_XenStorage-506b833c-f239-ad9a-350f-a7287ed3e259 PV Size 1.36 TB / not usable 7.77 MB Allocatable yes PE Size (KByte) 4096 Total PE Free PE Allocated PE PV UUID 5bhPOM-r7J0-2cSV-2CnR-WKpI-Vzue-AJorZZ # "/dev/sdb1" is a new physical volume of "1.36 TB" --- NEW Physical volume --- PV Name /dev/sdb1 VG Name VG_XenStorage-f6bce4ea-0bff-74f0-7a d517bd4 PV Size 1.36 TB / not usable 7.25 MB Allocatable yes PE Size (KByte) 4096 Total PE Free PE 132 Allocated PE PV UUID 2z9UKx-eTRo-I42j-O120-4F37-i5Is-edTbX8 Note If the new disk already contains a LVM partition, it should be automatically recognized as a new physical volume. In this case, the pvcr eate command is not necessary. The new storage can be added to the existing local storage, or it can be used to create a new distinct local storage. The first option has the disadvantage that the local storage is now dependend on two physical harddisks. This will double the risk of a failure. Alternative 1: Extend existing local storage To extend the existing local storage, use the vgextend command to add the new physical volume to an existing volume group. This command needs the volume group name as a parameter, so we run the vgdisplay command first. After execution of vgextend we should see the extra storage available in the volume group. The new size will also be displayed in the Citrix XenCenter for the local storage.

3 # vgdisplay --- Volume group --- VG Name VG_XenStorage-ece12464-dfb3-8c83-36dd-e88c9f2c6b65 System ID Format lvm2 Metadata Areas 1 Metadata Sequence No 1223 VG Access read/write VG Status resizable MAX LV 0 Cur LV 27 Open LV 26 Max PV 0 Cur PV 1 Act PV 1 VG Size 1.36 TB PE Size 4.00 MB Total PE Alloc PE / Size / 1.36 TB Free PE / Size 12 / MB VG UUID JrIxtn-2smY-Hvav-FzXk-Un7o-G07e-fzjAqU # vgextend VG_XenStorage-ece12464-dfb3-8c83-36dd-e88c9f2c6b65 /dev/sdb1 Volume group "VG_XenStorage-ece12464-dfb3-8c83-36dd-e88c9f2c6b65" successfully extended # vgdisplay --- Volume group --- VG Name VG_XenStorage-ece12464-dfb3-8c83-36dd-e88c9f2c6b65 System ID Format lvm2 Metadata Areas 2 Metadata Sequence No 1235 VG Access read/write VG Status resizable MAX LV 0 Cur LV 30 Open LV 28 Max PV 0 Cur PV 2 Act PV 2 VG Size 2.72 TB PE Size 4.00 MB Total PE Alloc PE / Size / 1.36 TB Free PE / Size / 1.36 TB VG UUID JrIxtn-2smY-Hvav-FzXk-Un7o-G07e-fzjAqU Note By chaining several physical disks you increase the failure risk. If any of the drives in the volume group fails, the whole storage including your existing virtual machines fails.

4 Alternative 2: Create new local storage To create a new XenServer storage, use the xe sr-create command. If this server is in a pool, we need to define the host the new storage is on, so we need to run the xe host-list command first. # xe host-list uuid ( RO) : 2b9dd54b a137-9a3519cb23fe name-label ( RW): server00 name-description ( RO): Default install of XenServer uuid ( RO) : f c3f-42fc-ad4d-3b4bd6084bab name-label ( RW): server01 name-description ( RO): Default install of XenServer uuid ( RO) : 9e27f96c-a5b8-477c-b7f1-beac0d9c2b3f name-label ( RW): server02 name-description ( RO): Default install of XenServer xe sr-create host-uuid=f c3f-42fc-ad4d-3b4bd6084bab shared=false type=lvm content-type=user \ device-config:device=/dev/sdb1 name-label="local storage 2" 01debcfa-0cbc-77af-5dae-269df31a8dfb Warning If your new disk already contains a LVM partition and has data in it (for example, if you were using this tutorial before, have copied data on the new storage and re-installed XenServer on the main disk), the xe sr-create command will delete all data. Using the new storage The new storage now shows up on the server's "Storage" tab in the XenCenter administration application. To use it, create a new virtual disk in the "Storage" tab of the virtual machine.

5 The new disk is now accessible as /dev/xvdb in the virtual machine. Just run fdisk /dev/xvdb and mke2fs -j /dev/xvdb1 and the new storage is ready for use. # fdisk /dev/xvdb Device contains neither a valid DOS partition table, nor Sun, SGI or OSF disklabel Building a new DOS disklabel with disk identifier 0xc6318a63. Changes will remain in memory only, until you decide to write them. After that, of course, the previous content won't be recoverable. The number of cylinders for this disk is set to There is nothing wrong with that, but this is larger than 1024, and could in certain setups cause problems with: 1) software that runs at boot time (e.g., old versions of LILO) 2) booting and partitioning software from other OSs (e.g., DOS FDISK, OS/2 FDISK) Warning: invalid flag 0x0000 of partition table 4 will be corrected by w(rite) Command (m for help): p Disk /dev/xvdb: GB, bytes 255 heads, 63 sectors/track, cylinders Units = cylinders of * 512 = bytes

6 Disk identifier: 0xc6318a63 Device Boot Start End Blocks Id System Command (m for help): n Command action e extended p primary partition (1-4) p Partition number (1-4): 1 First cylinder ( , default 1): Using default value 1 Last cylinder or +size or +sizem or +sizek ( , default ): Using default value Command (m for help): p Disk /dev/xvdb: GB, bytes 255 heads, 63 sectors/track, cylinders Units = cylinders of * 512 = bytes Disk identifier: 0xc6318a63 Device Boot Start End Blocks Id System /dev/xvdb Linux Command (m for help): w The partition table has been altered! Calling ioctl() to re-read partition table. Syncing disks. # mke2fs -j /dev/xvdb1 mke2fs (12-Oct-2008) Filesystem label= OS type: Linux Block size=4096 (log=2) Fragment size=4096 (log=2) inodes, blocks blocks (5.00%) reserved for the super user First data block=0 Maximum filesystem blocks= block groups blocks per group, fragments per group 8192 inodes per group Superblock backups stored on blocks: 32768, 98304, , , , , , , , , , , , , , , , Writing inode tables: done Creating journal (32768 blocks): done

7 Writing superblocks and filesystem accounting information: done This filesystem will be automatically checked every 30 mounts or 180 days, whichever comes first. Use tune2fs -c or -i to override.

8 # See also When adding extra disk drives, consider also adding the smartmontools. The new disk drives will fail at some time in the future. Install smartmontools on Citrix XenServer Links to the official Citrix documentation: