Raid Card controller for FC System

[Albert Graham]

Edward,

Most modern motherboards will all you to have 4 or 6 SATA drives 
connected, so the cheap solution is to use Linux software raid, that's 
the best bang for your buck you're gonna get :), on the other hand, if 
you're interested in higher spec try this:

$325 - http://www.3ware.com/products/serial_ata2-9650.asp

Fedora 8 kernel includes drivers for this card.

This card has lots of very nice features, firstly the drives can be 
configured as JBOD, so it can act as a simple controller allowing you to 
use Linux Software Raid, it has 256MB write cache, You can buy a BBU 
separately as shown here:

http://store.3ware.com/?category=2&subcategory=6&productid=BBU-MODULE-04

The nice thing about the above, is it does not sit on the same card - it 
uses an extender cable + a dummy slot (high or low profile).

Performance on these cards are excellent, "but only if configured 
correctly" - Use the right file system for the job.

The website states "delivering over 800MB/s RAID 6 reads and 600MB/s 
RAID 6 writes.", but you will not achieve this with 4  disks. you will 
probably achieve 2.5x your normal read/write performance, so if you're 
drives give you 100MB/s you can except around 250MB/s read using Raid 5. 
i.e. this card reads & writes to all drives in parallel - which is what 
you expect from hardware raid.

I have the 12 Port version on my desktop and have 8x1TB drives in a Raid 
5 array and I get 624MB/s+ writing and 750MB/s reading (both on a file 
size of 100G+).

http://www.g-b.net/mythbox1.jpg
http://www.g-b.net/mythbox2.jpg
http://www.g-b.net/mythbox3.jpg
http://www.g-b.net/mythbox4.jpg
http://www.g-b.net/mythbox5.jpg

Note: This card should not be confused with the old 955xx cards, they're 
not so good.

Other nice features are hot-swap and auto-rebuild, nice web interface as 
well a a useful  (but binary) command line interface - which allows 
monitoring IOPs and setting lots of lower level functions (such as 
drive-level cache etc..), it also has an A/V mode, when enabled it will 
not start verifying your disks in the middle of a job.

Make sure you have the same drives with the same firmware version, as 
this can cause performance problems. The monitoring tools will allow you 
spot a slow / problematic disk easily before they become a problem.

There is also a nice cabling solution - i.e. 1 to 4 breakout cable included.

BTW: This card is PCI Express x8 but will operate in slower or faster 
slots (mine is x16)

If possible use 3GB/s drives (SATA II), they'll give you the edge - I 
gain 50MB/s when this is enabled using 8 drives :)

Most smart-mon-tools functions work with the card as expected, in 
addition some, but not all power functions work, so you "can" issue 
"sdparm -C stop /dev/sdc" to spin down an entire array for example.

It took me a long time to get the performance I expected from this card, 
mostly due to Raid alignment and using XFS file system. - Ext3 is a dog 
on Raid 5 :(

Albert.





edwardspl at ita.org.mo wrote:
> Dear All,
>
> Which model / type of ATA Raid card controller is good for work with 
> New FC System ?
> Would you  please recommend ?
>
> Thank for your help !
>
> Edward.
>