RAID configuration

[Edgar Zapata]

At a DL380 G6 we're planning on having 2 160 GB disks for RAID0+1 and 4 250 GB disks for a RAID5.
Since we need at least 500 GB disk capacity.
I know we'll lose 1 disk, but we'll still have 750 GB for storage.
I'm planning on install W2K3.
Am I missing anything here?
I mean, will 250 GB disks affect the RAID 5 write-read performance?

Thank you

[Jupinder Bedi]

Go a Head . it will not effect anything the only thing you will loose is 250 GB space

[TTr]

> will 250 GB disks affect the RAID 5 write-read performance

It depends on what kind of i/o requirements you have for this server. What applications and databases are you installing and what kind of i/o activity do you expect to have.

To me there is a little bit of an imbalance here. You bought a G6 server with a P410i array controller which are quite powerful. And then you bought SATA disks. Why? Are the SAS disks so much more expensive than the SATA ones?

[Edgar Zapata]

Thank you all.
TTr, we haven't purchased yet.
It's a quick budget for an actual purchase we'll have to do.
I'm interested in listening to your suggestions here.
Yes, we planned on buying SATA disks, but how come you know they're SATA... I didn't mention anything about that.
Plus, why should we get SAS disks?
What features would make me pick SAS over SATA?

Thanks.

Edgar

[Edgar Zapata]

Did some reading here
http://findarticles.com/p/articles/mi_m0BRZ/is_6_23/ai_105884200/
I know the reasons now why I should be using SAS instead os SATA.

Thanks for the nuance.

[TTr · Accepted solution]

I order so many of these (servers and disks) that I know (without even looking) that the sizes that you mentioned are only available in SATA.

The SAS disks have a faster interface (6G) as opposed to 1.5G and 3G of the SATA disks. So the data i/o is faster. Also the SAS disks have a higher RPM, 10k/15k, compared to the 7200RPM of the SATA, so they can sustain i/o at a higher rate.

You should also buy the BBWC option for the P410i, 256MB or preferably 512MB.

More details here

http://h18004.www1.hp.com/products/quickspecs/13234_div/13234_div.html

[Edgar Zapata]

Hi TTr,
I must confesss I'm out of this.
what's that BBWC for?

thanks.

[TTr]

Battery Backed Write Cache. It is a battery kit that allows you to set up "write-cache" in the raid controller. Without battery you can only set up read cache only. It makes a big difference in the performance. Check out the URL I included above

[wobbe]

You need the BBWC to do raid 5 the entry level controller won't support raid 5.
But why use raid 5? I you want space and performance on a budget get 8x160 sata in raid 10 this will be much faster than what you got planned at the moment. The BBWC is still a very good idea!

[Edgar Zapata]

RAID 10?
I knew about RAID 6 where we have allowance for 2 drive failure.
Didn't know about RAID 10 unless you are referring to RAID 1+0...
In which case, we will be losing half the size we have, won't we?
But again, you are suggesting me to use SATA disks.
Gosh, I'm a little confused now.

We can't afford a bad performance here...
TTr already pointed out I should use SAS disks, which is my bet here.
I'm way more confident with SAS disks features.

So? Any more suggestions?