slow write speeds on LSI RAID controller card

[mac_angel]

running Win7 64bit, 12GB RAM, Core i7 930 stock, 64GB SSD for OS. I have an LSI 9240 8 port RAID card and a 9260 8 port RAID card with 512MB on board RAM. 4 x 2TB 5900 RPM SATA 2 Seagate hard drives and 2 x 2TB 7200 RPM SATA 3 Seagate hard drives, all in a single RAID 5 on the controller card. I've tried both controller cards and I'm getting really poor speeds, especially write speeds, dropping down to 14MB/second writing large video files over. I've ran tests on the hard drives and the RAID consistancy and I can't find any problems. Updated drivers, updated firmware. A friend of mine said it is because of the different speed hard drives, but googling it, all the forums I've seen say the same thing, that the RAID should perform as fast as the slowest hard drives, so they should be about the same as 6 x 2TB SATA 2 5900 RPM hard drives. Anyone have an opinion or any help?
CrystalMark speeds ~225MB/sec read, ~30MB/sec write.
I've also tried installing it into my gamer system. Core i7 2600K OC, 16GB RAM. Same speeds. Tried both sets of cables on both RAID cards. I read online somewhere that some motherboards don't like anything but graphics cards being installed in the PCI-e 16x slots. I've talked to MSI about this and they can't confirm or deny this.

 

[tokencode]

The above article reference is for log volumes, but the same applys for data volumes of a given size as well. If your database is primarily reads then yes you might get better performance with RAID 5, but if it is evenly read/write or primairly write, RAID 10 is definitely the way to go, here's a better explanation than I could give....



According to sql-server-performance.com, the best RAID configuration is dependant upon the number of I/O Reads versus I/O Writes. I have quoted the following from their website to help anyone else that may have the same question that I did.



When performance tuning a SQL Server, it is often handy to know if the disk I/O of your servers (and the databases on it) are mostly reads or mostly writes. This information can be used to calculate the ratio of writes to reads of your server, and this ratio can affect how you might want to tune your SQL Server. For example, if you find that your server is heavy on the writes, then you will want to avoid RAID 5 if you can, and use RAID 10 instead. This is because RAID 5 is much less efficient that RAID 10 at writes. But if your server has a much greater number of reads than writes, then perhaps a RAID 5 system is more than adequate.

One of the quickest ways to find out the ratio of reads to writes on your SQL Servers is to run Task Manager and look at the sqlservr.exe process (this is the mssqlserver service) and view the total number of I/O Read Bytes and I/O Write Bytes. If you don't see this in Task Manager, go to View|Select Column, and add these two columns to Task Manager.

The results you see tell you how many bytes of data have been written and read from the SQL Server service since it was last restarted. Because of this, you don't want to read this figure immediately after starting the SQL Server service, but after several days of typical use.

In one particular case I looked at, the SQL Server had 415,006,801,908 I/O bytes read and 204,669,746,458 bytes written. This server had about one write for every two reads. In this case, RAID 5 is probably a good compromise in performance, assuming that RAID 10 is not available from a budget perspective. But if the reverse were true, and there were two writes for every one read, then RAID 10 would be needed for best overall performance of SQL Server.

 

[tokencode]

BTW, I'm glad we fixed the OPs probablem because we totally hijacked this thread.

 

[FireWire2]

yes Indeed

 

[mac_angel]

lol, yea, no kidding.
suggesting new RAID cards really doesn't help much when I said what I have already. And a software RAID isn't so much a problem with the kind of rig I have. Thing was, it wasn't using ANY resources at all. I still think I'm getting shitty speeds considering. It is a hardware RAID card with 512MB on board RAM, and it should be a fast enough rig, but 250MB/sec read and 175MB/sec write, yes, it's better write then what I had before, but no where near where it should be. Part I'm confused on is I was getting 335MB/sec read at the beginning, and it's now down to 250MB/sec. I don't know what happened to loose that speed. I've tried playing around with things in the BIOS and the settings, but no luck.