Solved

# Calculating IOPS of current SAN and possible replacement SAN

Posted on 2011-05-11
3,396 Views
I'm currently in the early stages of replacing 2 IBM SANs with possible an 2 HP EVA 4400s.
In our current environment we have:
IBM DS 4300 (14) 2Gb Fc 146GB 10k drives
IBM DS 4700 (16) 4Gb Fc 300GB 15K drives
Can someone please give me a rought calculation on the IOPS of each of those SANs?  I should note that each are configured as seperate storage spaces.

I'm looking at replacing those with:
(2) HP StorageWorks EVA 4400 (24) 300GB  15K drives
What would be the IOPS of this kit?

Any input\feedback is greatly appreciated.
0
Question by:bermudahs

LVL 10

Accepted Solution

Here's a good IOPS calculator: http://www.wmarow.com/strcalc/
0

Author Comment

sorry didn't find that helpful as i couldn't plug in the type of hard drives i have
0

LVL 3

Assisted Solution

RAW IOPS you're looking at (using 120 for 10k and 180 IOPS for 15k)
DS 4300 (120 IOPS * 14 disks)- ~1680 IOPS
DS 4700 (180 IOPS * 16 disks)- ~2880 IOPS

The new array (180 IOPS * 24 disks)- ~4320 IOPS

Your RAID type also has a lot to do with the amount of IOPS you'll see.  What RAID type are you using on the current and new setup?  What is your read/write ratio?  You'll see less than these numbers at the host level once you account for RAID write penatly.

0

Author Comment

Let me get back to you in terms of what the RAID level on what the IBM SANs are currently using.
In the meantime - in order to get the 24 disks - 4320 IOPS, I'll have to configure the 2 EVA4400's as 1 mas storage?
0

LVL 55

Assisted Solution

If you wanted 24 disks in one you would buy one EVA4400 and one (or two) M6412A FC Drive Enclosure to expand it, not two EVA4400s. EVA4400 scales up to 8 drive enclosures, the starter kits have one enclosure included with them.

As already noted above it's the raw disks IOPS that matters as far as performance goes, an EVA with 24 disks isn't going to be significantly faster than an IBM DS series with the same amount.
0

LVL 16

Assisted Solution

I think you also need to take into account the IOPS bottleneck in the controllers as well.

The IBM DS range (based on the Engenio/LSI now NetApps DS range) has a well known bottleneck in the controller.
0

LVL 55

Assisted Solution

I didn't know of a controller bottleneck on Engenios unless you mean that the single controller models disable the write cache by default which leads to horrendous write performance with RAID 5 unless you force it to be enabled.
0

LVL 3

Assisted Solution

The controllers add a little overhead, but with spinning disks, it really all comes down to the disks.  Every storage vendor tries to sell you a product by trying to convince you that there's some magic inside their array that makes their spinning disks different from everyone else.  It all comes down to the disks.  Cache is nice and adds a lot of performance benefit, but if you write to disks faster than the cache can be flushed to disk, your cache will fill up and become useless.

So I guess my point is.  It all comes down to the spinning disks.

If you're using SSDs, or an array with a lots of DRAM cache (symmetrix) - Then it's a bit different.
0

Author Comment

closing.
0

Author Comment

I've requested that this question be closed as follows:

Accepted answer: 0 points for bermudahs's comment http:/Q_27031426.html#36047121

for the following reason:

0

LVL 16

Expert Comment

Too much input from experts
0

## Featured Post

### Suggested Solutions

Moving your enterprise fax infrastructure from in-house fax machines and servers to the cloud makes sense — from both an efficiency and productivity standpoint. But does migrating to a cloud fax solution mean you will no longer be able to send or re…
In the modern office, employees tend to move around the workplace a lot more freely. Conferences, collaborative groups, flexible seating and working from home require a new level of mobility. Technology has not only changed the behavior and the expe…
This video teaches viewers how to encrypt an external drive that requires a password to read and edit the drive. All tasks are done in Disk Utility. Plug in the external drive you wish to encrypt: Make sure all previous data on the drive has been …
This Micro Tutorial will teach you how to reformat your flash drive. Sometimes your flash drive may have issues carrying files so this will completely restore it to manufacturing settings. Make sure to backup all files before reformatting. This w…