Expand datastore on diffrent raid configuration

[ESXIdto]

Hello Community,

We are trying to expand a VMFS datastore on an ESXI 6. the configuration is the following:

1st Datastore : 6 Disk of 2TB with Raid 5 configuration

Just Added 2 Disk of 2TB with raid 0/raid 1

My question to the community is the following:

If I expand the 1st datastore to use  the availiable disk space while the raid configuration is diffrent. Would this make a performance/consistancy issue ?

Thanks for the help.

[golddiggie]

I've always extended the LUNs to increase the datastore capacity. It would have been easier, IF your SAN could get the additional drives added to the RAID 5 volume, then expand the RAID and related LUN setup. Then you could simply do a scan of the datasore/HBA and then expand the datastore to use more of what's presented.

[a_p_ · Accepted solution]

I agree with golddiggie​, expand the existing RAID set/logical volume if possible, rather than adding an extend with a different RAID level.

Although such a configuration will likely work, it may cause performance issues, similar to mixing LUNs with different tiers.

From https://kb.vmware.com/s/article/2000643

Mixing LUNs with different speeds can affect the performance of your extended VMFS. Therefore, it is better to have all extents presented from the same storage array.

André