Question on raid 1 mirroring.

I always thought that the read speed should be faster on a mirrored drive, since you have two drives that the same data can be read off or if multiple files want to be accessed at the same time, read speed can be improved since one file could be read off one drive and another off the other drive.

But i believe that software raid (through windows server) would be better at this than a hardware raid controller.

Im mainly looking at improving reliability on a system than speed itself, but i dont really want this to affect speed if possible.

Alot of things ive read seem to conflict, but i always thought that speed was a benefit, but some sources say the opposite.


geek_nzoomed, Feb 9, 9:20 pm

There may be very minor benefits in read speed, but write speed will suffer over a single disk

As for software RAID vs hardware that depends on the hardware yiu choose

geek_vtecintegra, Feb 9, 11:32 pm

A mirrored RAID should significantly increase read speed. If you have a good RAID controller, you'll get close to double the performance. I've run RAIDs for years and have seen it happen.

Check out some benchmarks online for proof.

geek_suicidemonkey, Feb 10, 12:03 am

RAID 0 is great - just ensure you have *excellent* backup and recovery systems in place.

geek_r.g.nixon, Feb 10, 12:21 am

It depends on the software. Back in the day we used to use raid 1 on Novell servers as the software was particularly good at sharing the read load on multi-user systems with that setup. Some raid arrays aren't really geared up for raid 1 performance though (or rather, they are designed for redundancy rather than performance), and you won't get much on a single-user system anyway as you'll rarely be doing two simultaneous different reads. You need to check out the software and specs for the hardware you're looking at. Raid 0 is for performance, raid 1 for redundancy. If you want both, use four drives and both.

geek_tillsbury, Feb 10, 12:25 am

Its an HP proliant server, dont know the exact model from the top of my head, redundancy is the most important thing for me at present.
Write speed should not be an issue, since most things are being read from the server and there is not huge amounts of data written each day.

I expect that if the RAID controller on the motherboard is fairly decent then it would do a better job than just using windows to mirror the disk?

geek_nzoomed, Feb 10, 1:04 am

I've just the onboard RAID controllers for years with no issue. Definitely better than a software RAID (if that can even be done?).

geek_suicidemonkey, Feb 10, 1:25 am

Yep you can software RAID. My server runs a ZFS (RAID-Z) array completely inside its BSD operating system.

geek_lugee, Feb 10, 2:34 am

If you have 3+ drives under 600GB then RAID5 would be the way to go. If 2 Drives then RAID1, if you have a lot of drives (6+), or they are bigger than 600GB then RAID6 would be the way to go, but you have to pay for a separate licence for RAID6 on a lot of HP RAID controllers. On HP gear if it's got a decent hardware RAID controller - which I think is everything over an ML110 which isn't really a server.

geek_pyro_sniper2002, Feb 10, 4:04 am

Its an ML110, ive got the array building as we speak, it looks likt it will take a few hours to build, there is about 150GB of data on there presently.

It looks like a reasonable RAID controller, but will be interesting to see the performance.

geek_nzoomed, Feb 10, 5:16 am

Is it a separate controller or just built into the motherboard? Either way it's probably fine for light duties.

geek_pyro_sniper2002, Feb 10, 5:37 am

Its onboard the motherboard.

Its just a basic file server, so i think it should suffice. Any increase in read speed will only be a good thing though.

geek_nzoomed, Aug 28, 11:08 pm