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No. of LUNs for RAID 1 in FC60.

Anu Mathew
Valued Contributor

No. of LUNs for RAID 1 in FC60.

Hi all,

Attached is a simple diagram of our proposed plan to connect two Servers, HP1 and HP2 to the same FC60 with 4 enclosures with 6 drives each.

Mirroring 1 holds
====================
A) Data Dump+S/w logs=145 GB.
B) translog+dumps=30 GB.

They both are write intensive.

In figure 1, A and B are on a single LUN (Mirroring 1) and has 2*3=6 drives.

In figure 2, A gets its own LUN (2*1=2 drives) [Mirror 1A] and B gets its own (2*2=4 drives) [Mirror 1B].

Which one is going to be of better performance?

Thanks a lot in advance for your time and suggestions.

Regards

Anu Mathew
5 REPLIES
Anu Mathew
Valued Contributor

Re: No. of LUNs for RAID 1 in FC60.

Oops, I missed the exact attachment. Please find herewith the right picture.

Sorry for inconvenience.

Regards

Anu Mathew
Pedro Sousa
Honored Contributor

Re: No. of LUNs for RAID 1 in FC60.

sorry Anu, but I cannot understand your draw!! So, I'll just advise you to use Raid 1/0 instead of Raid 1.
Raid 1/0 will give you better performance and the same redundancy. It has mirroring capacity, plus striping!
good luck.
Anu Mathew
Valued Contributor

Re: No. of LUNs for RAID 1 in FC60.

Hi,

I admit that the diagram is bit complex, and that was the simplest one I could make for our developers. I am trying to put the question in a straighter way:

We are employing FC60 disk array and so we have the option for going for a hardware RAID 1 over a total of 8 nos 73 GB drives.

In FC60, if RAID 1 is implemented, RAID 0 also comes along. We are opting for optimum performance. In FC60, should I create separate mirrored LUNs, create the VGs and then LVs or one entire mirrored LUN with single VG is enough?

One filesystem that we are to create will require the mirrored capacity of 6*73 drives( ie, 50% of the total capacity), and the other one will require mirrored capacity of 2*73 GB, (again 50% of that).

What I want to know is that, should I create separate LUNs (one on 6*73 GB drives, the other on 2*73GB)? OR, should I create only one Mirrored LUN over the entire 8 disk drives. Which one is going to give me best performance? The filesystems are write-intensive in nature.

I do hope that this time, I have expressed it in a better way.

Regards

Anu Mathew

Which way I can have the max performance?

Thanks a lot in advance for your patience, time and expertise.

Regards

Anu
Mark van Silfhout
Trusted Contributor

Re: No. of LUNs for RAID 1 in FC60.

The best practice for performance is to have multiple luns in a VG so you can balance the load of the controllers (ie, lun0 uses c3t0d0 as primary and lun1 uses c5t0d1 as primary and both will be in the same VG).
The user manual of the FC60 has some good lecture about performance, see page 56. Also take a look at page 70, the recommended configuration for 4 disk enclosures and high performance.

Regards,

Mark
Pedro Sousa
Honored Contributor

Re: No. of LUNs for RAID 1 in FC60.

Hi Anu!
Mark is right... besides controllers, it will also balance SPs.
So, it would be best to create 2 LUNs.