This article is intended for administrators wishing to understand storage resiliency options within a host when utilizing SvSAN.
Note: All images are clickable for enlarging, or can be opened in a new tab
Resolution/Information
Summary
SvSAN supports both hardware RAID controllers, where the VSA VM sees a JBOD disk, meaning that the RAID options provided by the controller are all fully supported, from RAID0, 1, 10 to RAID5/50 RAID6/60.
The VSA is then dependent upon the configuration of this RAID as to the performance provided through to the VSA, such as parity RAID providing good capacity from HDD drives however poor write performance without a controller cache module.
Or if the controller disables the write cache having detected SSDs in use:
https://support.stormagic.com/hc/en-gb/articles/5663966615965-SvSAN-and-HPE-SSD-Smart-Path
Should an HBA be in use the individual drives are passed directly through the hypervisor to the VSA to manage.
Note that hardware RAID volumes assigned to the VSA via RDM and JBOD enable an easy grow of a pool. e.g. grow the RAID volume via the controller, and the VSA will automatically pickup the new size.
https://stormagic.com/doc/svsan/6-3-P2/en/Content/increase_storage_vcsa_plugin_rdm.htm
A software RAID cannot be dynamically grown. e.g. a mirror break, pool delete and recreate is required:
https://support.stormagic.com/hc/en-gb/articles/9044481229981-SvSAN-Plex-delete-break
As such a JBOD pool, not a RAID0, is recommended on a hardware RAID disk.
Software RAID
SvSAN VSAs leverage Linux MD internally to provide software RAID 0 (stripe), RAID 1 (mirror) and RAID10 functionality.
This can be leveraged for cache SSDs, or pool disks.
RAID5 functionality is NOT provided by sofware RAID due to poor write performance without a cache module for parity calculations and the risk of the write hole. However as stated previously in this article parity RAID can be consumed from a hardware RAID adapter.
A JBOD over multiple disks, becomes a concatanation. e.g. full capacity but performance of one drive.
Plugin functionality at deployment:
The SvSAN vCenter plugin enables the assignment of storage ot the VSA as a single RDM, VMDK or skip.
By selecting the Advanced options it is possible assign multiple disks as either JBOD or software RAID1.
It is NOT possible in the plugin to create a software RAID10 however disks may be added as JBOD to speed deployment, and then the JBOD deleted and a RAID10 provisioned, via the VSA WebGUI.
Scroll down within this window to hit OK.
VSA WebGUI functionality:
The VSA WebGUI enables provisioning of all available software RAID types and hot spare configuration.
Software RAID10:
Hot spares may also be configured for software RAID volumes via the VSA WebGUI, by selecting the pool and selecting Add Hot Spare.
Selecting the hotspare disk to assign.
Pool display, including hot spare disk.
See Also
Comments
0 comments
Article is closed for comments.