PDA

View Full Version : Raid 5 performance


Dende
12-05-2008, 02:34 PM
I have put together a new i7 system at newegg. and I am thinking about getting 3 1TB

drives for the operating system and storage. I was thinking about part. a 300 gig system

drive and then use the rest for anime. My question is if I use a single raid 5 setup for both

the os AND storage will I see an issue when I am downloading at 1.2Mb/s AND trying to

play games at the same time?? My thought is that it will be accessing the same physical

drives at the same time and not two different drives like I am use too now. And sorry if this

is a n00b question please don't fire me :P

houkouonchi
12-05-2008, 02:40 PM
I seriously doubt a download at only 1.2MB/sec would effect game loading in anyway on a decent raid controller.

SockMan!
12-05-2008, 02:51 PM
Probably woudn't impact performance much even on a non-RAID disk. If you were doing disk-to-disk multi-gigabyte file transfers, then yeah you'd probably benefit. But 1.2 megabits/sec download is nothing.

Syntax Error
12-05-2008, 02:59 PM
Well a single hard drive can respectably do around 60-80MB/s, I doubt a RAID 5 array with 1.2MB/s load would be much. :p

Dende
12-05-2008, 03:00 PM
well again I'm use to having a much slower system and I can tell on my current system that when I download on the os drive it causes lag in WoW and other games. When I download to my second drive I don't see the lag. I just wanted to make sure that if I spent all this money that I set it up correctly :)

Second question is Raid 5 fast compared to a stand alone drive?? Should I have an OS drive (maybe a small 300giger) and then a Data aray??

Danny Bui
12-05-2008, 03:40 PM
Second question is Raid 5 fast compared to a stand alone drive?? Should I have an OS drive (maybe a small 300giger) and then a Data aray??

If you're using a true hardware RAID controller, yes a RAID5 setup will be faster than a single drive. But if you're using the onboard motherbaord RAID, no, RAID5 will usually be slower than a single drive.

Yes get a separate OS drive, like the WD6400AAKS since it's the current best bang for the buck hard drive now in terms of price and performance close to Velociraptors, and a data array.

Also just to make sure you know this: RAID5 is NOT backup.

jcolby
12-05-2008, 04:01 PM
If you're using a true hardware RAID controller, yes a RAID5 setup will be faster than a single drive. But if you're using the onboard motherbaord RAID, no, RAID5 will usually be slower than a single drive.

Are you sure about this? I know from experience that Raid 5 Writes are slower on a software RAID but I seem to remember than my software raid 5 reads were much faster. More drives streaming data and all that.

Blue Fox
12-05-2008, 04:55 PM
Software RAID read speeds are fast because no parity needs to be calculated; writes however, are not.

Dende
12-06-2008, 04:42 PM
If you're using a true hardware RAID controller, yes a RAID5 setup will be faster than a single drive. But if you're using the onboard motherbaord RAID, no, RAID5 will usually be slower than a single drive.

Yes get a separate OS drive, like the WD6400AAKS since it's the current best bang for the buck hard drive now in terms of price and performance close to Velociraptors, and a data array.

Also just to make sure you know this: RAID5 is NOT backup.

Raid 5 is NOT backup???? I thought that was the whole point of raid 5 so that if one drive dies you just have to replace it without losing any data. Is this not the case now?? I am thinking along the lines of a server (like I am use to dealing with).

Danny Bui
12-06-2008, 05:10 PM
Raid 5 is NOT backup???? I thought that was the whole point of raid 5 so that if one drive dies you just have to replace it without losing any data. Is this not the case now?? I am thinking along the lines of a server (like I am use to dealing with).

RAID of any sort (except for RAID 0 of course) guarantees uptime and protection against hardware failure. However, RAID does not protect against accidental or malicious deletion. corruption, loss, or infection of files stored on a RAID array. Thus, RAID 5 is not backup.

geiger
12-06-2008, 08:15 PM
I don't think the 1.2MB write stream by itself is the cause of the lag. By "downloading" I assume you are referring to the use of torrents. Seeding multiple large torrents can definitely cause a strain on your system.

In your case raid may not be the fixall you might think it'd be. In your case I'd suggest having multiple separate drives(JBOD). Put the incoming torrents on one drive, the completed on another, and if you have the ports/drives WoW on a different drive.

Same logic applies to video conversion processing, reading and writing the project from the same drive will be a lot slower than having a read drive and a write drive/scratch drive.

Dende
12-06-2008, 08:38 PM
RAID of any sort (except for RAID 0 of course) guarantees uptime and protection against hardware failure. However, RAID does not protect against accidental or malicious deletion. corruption, loss, or infection of files stored on a RAID array. Thus, RAID 5 is not backup.

AHHHH I see what your saying :) gotcha ;) I'm not woried as much about deletion or corruption as much as hardware failure's I just want to be able to replace a drive if it dies without losing data. If I mess it up then its my fault but if the drive fails then its the hardwares falt. I just want to eliminate 1 way of data loss :)