Which drives are better for RAID?

[cpjust]

Hi,
I just wanted to see if anybody here knows a lot about RAID and can answer this.
I currently have 3 Seagate Barracuda 500GB SATA (model ST3500320AS) drives, and which are configured in RAID 5 (and RAID 0 which I plan to move to 5 soon), but I was wondering if the Seagate Barracuda ES (model ST3500630NS) would be a better choice to use for drives in a RAID 5 configuration? The Enterprise drives only have 16MB cache instead of the 32MB that mine have, but it says they're designed for "Dynamic, capacity-intensive RAID systems".
Since they have less cache, I would guess they'd be a little slower than mine (unless there's something about them that makes them work better in RAID)?

 

[wahnula]

My take on this is get the best drives you can afford. If you can't go SCSI, go SAS.

Highest reliability rating for 24 x 7 operation

When I see SAS as an option for the interface as with the ES, I know it's a much tougher drive. I would choose the ES for your application.

Tony

Users helping Users...

 

[cpjust]

This is actually for my home PC, so I think SAS... would be a bit much.
I'm starting to wonder if there's a specific reason why the non-ES version says "Desktop RAID 1 or 0 systems (<3 drives in one system)

 

[technome]

The Enterprise drives only have 16MB cache instead of the 32MB that mine have....

Depends on the raid adapter/interface, but many true hardware raid interfaces turn off drive caching as it actually lowers array performance and interferes with adapter data safety mechanisms. For the performance aspect, the cache is often disable because there would be added delays with requests for data which is not in the drives cache, plus the struggle to maintain data intergrity between two caches, which often would be the case with Enterprise class I/O.

"..designed for Dynamic, capacity-intensive RAID systems"....
Drive manufacturers are fully aware many true hardware raids turn off the cache. This statement is called dazzling with BS.
If you raid interface is a wanabe raid or does not have a decent caching mechanism, then drive caching enabled may help.



........................................
Chernobyl disaster..a must see pictorial

http://www.kiddofspeed.com/default.htm

 

[cpjust]

I'm using the Intel RAID that's built into my ASUS P5K3 Deluxe motherboard. I don't think it's 100% hardware RAID, since Linux sees 3 individual hard drives whereas Windows sees one big volume.

 

[Dog6880]

so is 32 MB cache for a RAID 5 array not something that matters and 16MB would be just as well?

 

[technome]

Unless the raid is designed to use the drive cache, none that I have used are, it does not matter how how large the drive cache is, just BS by the manufacturers. As a single drive in a PC or a single drive hanging off a non raid adapter, then the cache comes into play.


........................................
Chernobyl disaster..a must see pictorial

http://www.kiddofspeed.com/default.htm

 

[cpjust]

My motherboard (ASUS P5K3 Deluxe) uses an Intel ICH9R RAID chip, and in the configuration program it has options for enabling Hard Drive Write Cache & Volume Write Cache. So I'm guessing it would matter in my case, right?

 

[technome]

If you can make a change, and the change holds after a reboot (not grey out or it reverts), then it is using the drive cache.


........................................
Chernobyl disaster..a must see pictorial

http://www.kiddofspeed.com/default.htm