RAID Read Performance

[sivam]

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

[Peter Mattei]

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

[sathish kannan]

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

[Peter Mattei]

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

[siva baskaran]

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

[John Kufrovich]

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.

[Peter Mattei]

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

[sivam]

Yes I got it.

[Peter Mattei]

Great!
What about some points? ;-)

[sivam]

Thanks friends