topic RAID Read Performance in HPE EVA Storage

RAID Read Performance

sivam — Sat, 18 Nov 2006 23:51:12 GMT

Hi,
For Read perfomance Raid 5 is good compare to RAID 1+0.
I require a document which shows READ Performance is good for implementation (RAID 5 or RAID 1+0) I am expecting for EMC Products.
Thanks in Advance
Sivam

Re: RAID Read Performance

Peter Mattei — Sun, 19 Nov 2006 03:35:05 GMT

Well, if you need such a statement for an EMC product, why dont you ask EMC?
You know there is RAID theory and practical implementation in a product which matters!!

Cheers
Peter

Re: RAID Read Performance

sathish kannan — Mon, 20 Nov 2006 01:50:31 GMT

Sivam,

RAID technologies are comman to all platforms. so if you think RAID 5 is better use RAID 5. There is not difference between different vendor implementing RAID technologies.

Regards
sathish

Re: RAID Read Performance

Peter Mattei — Mon, 20 Nov 2006 04:12:22 GMT

Sathish

Sorry, but you are definitely wrong!
Especially with RAID5 there is huge impact on performance by architecture.
A very good implementation like on an XP10000 or XP12000 for example reduces the RAID5 penalty/overhead massively by keeping writes in cache as long as possible and writing sequential stripes instead of small chunks which would mean multiple reads and writes!

Your quote was only correct if you were talking about server based software implemented RAID.

Cheers
Peter

Re: RAID Read Performance

siva baskaran — Mon, 20 Nov 2006 06:45:33 GMT

Hi,

i am also thinging likewise RAID 5 concept is same as a server level focus and there is something will differe depends on technology performance wise because suppose when u r studying theory of raid concepts from different docs from different vendor that will little different concept will available according their thcnology

thanks
siva

Re: RAID Read Performance

John Kufrovich — Mon, 20 Nov 2006 08:36:45 GMT

Everyone,

Read performance is comparable between the different RAID levels. With the exception of RAID1+0, it has the potential to be a little faster due to load balancing.

With writes there are various penalties between the RAID levels.

Re: RAID Read Performance

Peter Mattei — Mon, 20 Nov 2006 12:08:37 GMT

Upps!
Indeed; my replies were related to WRITES of course!!

In reads RAID5 can even be faster!

If you lets say have 20 disk in RAID1 a single stream actually reads from 10 disk only.

If you have RAID5 on the same 20 disks with lets say 4&1 a single stream will actually read from 16 disks!

In a multi threaded environment I would not expect much difference!

Cheers
Peter

Re: RAID Read Performance

sivam — Thu, 07 Dec 2006 09:48:57 GMT

Yes I got it.

Re: RAID Read Performance

Peter Mattei — Thu, 07 Dec 2006 09:53:00 GMT

Great!
What about some points? ;-)

Re: RAID Read Performance

sivam — Mon, 11 Dec 2006 13:47:32 GMT

Thanks friends