MSA 2040 question

[schano]

Hello, i have a MSA 2040 and i have some questions.

1. What is the difference between Disk Group Type "Virtual" and "linear"?
2. What are the advantages of Virtual vs. Linear?
3. For what the pools be used?

In MSA are installed 17x 15K 600GB hard disks and 2x 2TB 7.2K hard disks.

I would like to set up the following configuration:
• RAID 10 with 16x 600GB 15K HDD + 1 Spare 15K 600GB
o 1 Volume 4.8 TB
• RAID 1 7.2K 2x 2TB hard drives
o 1 Volume 2TB

Which Disk Group type makes more sense here "Virtual" or "linear"?

[Torsten.]

To make it short and simple - "linear" is the old style used by the G1 to G3 model already. You create a vdisk on a number of disks, let's say 5 disks for a RAID5 and create LUNs within. Then another vdisk ... and so on. The vdisks already set the RAID level for all LUNs inside.

With virtual you create a bunch of disks as a pool and all LUNs inside use all available disks on their LUN specific RAID level (just like the EVA / P6000 disk array did) - so as an example even a 2 disk mirror may use 10 disks - so it is much faster and the I/O does not hit only 2 disks while other disks are idle - more reliability, more performance.

The SMU user guide has more details.

[slesru]

> so it is much faster

Hello!

Just got access to our MSA 2040, and found that all luns there are linear.

Admin claims that virtual volumes far slower, and showed simple dd test,

virtual pool write performance is twice lower than linear.

Could you tell me is this expected?

Thank you!