Create a block backstore
The following commands create block backstores. Use the cd command to change to the /backstore/block directory.
/> cd /backstore/block
/backstore/block
Use the create command to create two block storage objects.
/backstores/block> create name=LUN_1 dev=/dev/xvdd
/backstores/block> create name=LUN_2 dev=/dev/xvde
Create a fileio backstore
The following commands create a fileio backstore. From the targetcli shell, use the cd command to change to the /fileio directory.
/> cd /backstore/fileio
/backstore/fileio
Use the create command to create a fileio storage object.
/backstores/fileio> create LUN_3 /root/disk1.img 5G
List the backstores
Use the ls command to view the backstores.
/> ls /backstores
o- backstores ………………………………….. […]
o- block ……………………….. [Storage Objects: 2]
| o- LUN_1 … [/dev/xvdb (10.0GiB) write-thru deactivated]
| o- LUN_2 … [/dev/xvde (10.0GiB) write-thru deactivated]
o- fileio ………………………. [Storage Objects: 1]
| o- LUN_3 .. [/root/disk1.img (5.0GiB) write-back deactivated]
o- pscsi ……………………….. [Storage Objects: 0]
o- ramdisk ……………………… [Storage Objects: 0]
Note that the block storage objects have write-thru deactivated and the fileio storage objects have write-back deactivated by default.
The fileio storage objects can support either write-back or write-thru operation. Write-back enables the local filesystem cache, which improves performance but also increases the risk of data loss.
Specify “write-back=false” when creating the fileio storage object to specify write-thru operation. For example:
/backstores/fileio> create <name> <file> <size> write_back=false
See the following for more information about backstores: http://linux-iscsi.org/wiki/LIO
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