This post is more than 5 years old
21 Posts
0
781
metaLun
Hi Guys,
Is it possible to create a metalun with one LUN on 1TB SATA and second on 2TB SATA?
My intial reaction on this is why not, but keen to see what the actual answer is and it is better to have the disks all the same size.
Thanks
Dougie
jps00
392 Posts
0
March 23rd, 2011 04:00
Well, technically a MetaLUN is only one LUN.
What I think you're asking is, "Can I create a MetaLUN with two components, one based on 1 TB SATA drives, and the other on 2 TB SATA drives?"
The answer to this question is "Yes", by using a concatenated MetaLUN.
The whitepaper EMC CLARiiON MetaLUNs: A Detailed Review explains how to do this and the implications. EMC CLARiiON MetaLUNs is downloadable from Powerlink.
RRR
1 Rookie
1 Rookie
•
5.7K Posts
1
March 23rd, 2011 02:00
It's possible, no worries there, but thinking of performance this might not be a good idea. Having said that, putting LUNs on SATAN isn't a good idea in the first place unless it's for streaming data, like video or backup or archived data.
I always calculate IOps per GB and whenever I create METALUNs I'll try to use RGs with comparable performance. So a RAID5 (41) RG using 146GB 15k disks gives you 5 x 180 = 900 IOps. If you carve out 1 large LUN this LUN has 900 IOps at it's disposal. If you now need a LUN twice as large but also twice the performance, you need a similar RG or a RG that has 900IOps available for the new METALUN component. This could come from a second RAID5 (41) 146GB15k RG which you completely use up or perhaps a RAID5 (9+1) 300GB15k RG which is now only 50% used (performance, not capacity).
Does this make any sence ?
douglas_carson2
21 Posts
0
March 23rd, 2011 06:00
Thanks guys for the posts.
I have managed to convince the client to take a different tact to no meta LUNs required.
Cheers
Dougie