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RAID 5 verry slow on Starkeh S354UFER

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August 19, 2011 3:00:34 PM

Hi,

I have a 4 bay StarTech RAID enclosure (S354UFER) with 4x2GB Smasung Spinpoint Drives. RAID 0 was very fast but RAID 5 is slower than my other UDB2 drives to write (I am using FW800 for RAID). Is this normal?

I am considering switching from RAID 5 to 10. I know it will give me less storage but it will be fast and secure (I gather I can loose 1 drive without data loss). I assume this is fast to write as well as read.

Everybody seems to be recommending RAID 5, odd they do not mention how slow to write it is;(.

All advise gratefully received.

Ben


a b G Storage
August 19, 2011 5:50:33 PM

Ben

RAID5 is fast... It just what is the raid engine that the raid was built on...

My eBOX-R5 with five 3.0TB Hitachi 5400rpm via Mobo internal SATA port (using eSATA bracket). I was able to transfer at 250MB/s under RAID5.

I guess the PLX - OXUFS936QSE's IO processor does not have enough power to calculate the parity bit for the raid5.

So it's fast if you are use/buy the correct one.

One of my post that shows the RAID5 system of my client was able to transfer over 1000MB/sec.
a b G Storage
August 21, 2011 12:59:19 AM

RAID 5 is not the fastest, RAID 0 is faster than RAID 5 for the same number of spindles. RAID 5 also incurs a write penality for parity calculations. Unless you have a dedicated hardware RAID controller WITH a processor you will actually steal CPU cycles for these calcs on RAID 5. RAID 5 is really only good for mass storage or write once, read many scenarios. If you want random IO speed, go RAID 0 or RAID 10.
a b G Storage
August 30, 2011 9:42:29 PM

There are 1000's of raid5 using out there for database server...
No one in the right mind would use software raid

I would not use raid0, for about $100.00 hardware raid controller deliver over 230MB/sec.

If you need speed use SSD, not RAID0
!