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12H autoraid vs. 30FC

State Farm Unix Support
Occasional Visitor

12H autoraid vs. 30FC

If I configure a 12H autoraid to force all it to be all RAID 1/0, why don't I just use an 30FC (or other model) array instead and configure that as all RAID 1/0? Doesn't forcing a 12H to RAID 1/0 defeat the purpose of an Autoraid? Is there any advantage to using a 12H in this way vs. 30FC?
7 REPLIES
Patrick Wallek
Honored Contributor

Re: 12H autoraid vs. 30FC

You can NOT configure an AutoRaid 12H to be entirely Raid 0/1. It's impossible. The AutoRaid 12H has "smarts" that is uses to figure out whether it needs to put data on as Raid5 on Raid 0/1. The level of usage of Raid 0/1 depends on the space on the AutoRaid that you do not have configured into a LUN.

I would NOT recommend using an AutoRaid. I would go after the FC30 in a heartbeat. I think you will find MUCH better throughput with the FC.
State Farm Unix Support
Occasional Visitor

Re: 12H autoraid vs. 30FC

Maybe force is the wrong word. By limiting the size of the LUNs so that they take up somewhat less than half of the space available on the array, won't that cause everything to remain RAID 1/0? That's what I see in several other entries in this forum. That also was mentioned by one of our CEs.
Patrick Wallek
Honored Contributor

Re: 12H autoraid vs. 30FC

If you limit the size of your LUNs then, yes you can make it so that the data is written as 0/1 and that will increase your performance. As you increase the size of the LUNs, and your free space decreases, then the the 12H will automagically figure out which data to write as 0/1 and which to write as 5.

If you just want RAID 0/1 then don't bother with the AutoRaid. Get a JBOD (like a Jamaica), make sure you have the mirroring software installed, and do it that way. You'll probably see better performance.

(By the way, if you know Wayne Gierman, tell him I said Hi. If he wonders who I am, tell him I used to work with Stan and Tinker at API.)
State Farm Unix Support
Occasional Visitor

Re: 12H autoraid vs. 30FC

Well, that's why I'm questioning the use of the autoraid in that way. Users weren't satisified with performance, and someone came with idea of configuring the LUNs on the 12H to only take half the space. I agree with your JBOD recommendation.

Wayne sits next me, but the dog is on vacation this week. I'll tell him you send greetings.
A. Clay Stephenson
Acclaimed Contributor

Re: 12H autoraid vs. 30FC

Hi Guys,

I would tend to agree with Patrick concerning the performance of a 12H but you can configure a 12H so that its performance is quite good.
1) Create each vg comprised of 2 LUNS of equal size. LUNa should be primary path controller X (alt Y); LUNb should be primary path controller Y (alt X). This utilizes both external SCSI paths for maximum performance.
2) Each lvol should be striped across both LUNS in the volume group for the same reason.
3) As you indicated, run them at about (50-60%) capacity leaving the remainder as unconfigured LUNS. Yes, you waste disk but the performance is worth it.

These steps bring the performance levels up to a comparable level AND don't overlook one of the best features of an AutoRAID - when a drive fails just plug one in and walk away.

My 2 cents, Clay


If it ain't broke, I can fix that.
Bill McNAMARA_1
Honored Contributor

Re: 12H autoraid vs. 30FC

it takes me a few hours of wait to bind an FC30 lun (even a small R1) Autoraid is instant... when my DBA asks me for 200M device file I can have it in 10secs.

AutoRAID is sold for its automatic control. If you are really worried about performance, don't get it. Get the FC array it using fibre not SCSI.

If you want serviceability and even faster than the FC30 in terms of internal disk busses, get an FC60 in split bus mode.

If that's still not fast enough, get an XP48.
Not big enough, get the 512.

It really depends. My AutoRAIDs have been just fine for developers compilations in terms of speed. Data's protected and they only use it from 9 to 5... perfect.

Later,
Bill
It works for me (tm)
Mark van Silfhout
Trusted Contributor

Re: 12H autoraid vs. 30FC

Hi,

using a JBOD would mean the RAID protection will be done by software instead of hardware, where hardware RAID protection is quicker and more reliable.
I agree with Clay that, if properly configured, the 12H can achieve an acceptable performance, but if this is not enough a VA7x00 or an XP48 would be a good (but more expensive) alternative.

Regards,

Mark