Raid. Is it worth it?

baldzone

baldzone

baldzone

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Complete noob to raid setups!

My main rig is long overdue a reinstall. Getting annoying little gremlins (no virus' or spyware reported) and am thinking of switching from XP to Vista.

It it worth going for a raid setup of would it be just as quick and reliable to get a velociraptor?

Nothing annoys me more than waiting for ages for a machine to boot up!

Ideally I'd like a faster read time and with some form of easy backup feature (although I do frequently back up important files).

What do the experts recommend? :D
 
RAID0 is an easy way of gaining a performance boost, but you need to go about it the right way. Use RAID where you going to see a benefit - i.e., for the OS partition and program/game file storage where disk transfer time is most noticeable. It's not necessary for general storage areas, and using RAID0 incurs certain additional risks compared to a single drive.

The downside of RAID0 is that both drives are needed for it to work, failure of one drive loses the whole lot. Secondly, recovering a corrupted RAID0 array is difficult - it's akin to shredding your files and spreading the bits over 2 drives. The extra complication of having the RAID controler keep track of all the bits means that ordinary recovery tools often don't work. If you go RAID0 you must have a reliable backup routine.

The best solution is a couple of small-ish drives in RAID0, and a third drive for general storage and space for the backup of the RAID array. Drives from 150-500GB are good for the RAID, if using the latter then partition the 1TB array to give you a smaller area for the OS (say, 150GB) and the remainder for games or whatever. The reason for doing this is it's easy to image the smaller OS partition [the part most likely to get corrupted] and store it elsewhere.

For backup use Ghost or Acronis (or something similar). Easy to schedule it to make a backup image once a week.

Personally, I just use a 300GB Velociraptor rather than a RAID. It's more expensive and data transfer slower (although access times are faster). I've used all sorts of RAIDs in the past - RAID 0, 1, 0+1, 5, and they all have pro's and con's. I had some spectacular failures of RAID0 arrays and lost data as I wasn't as conciencious about making backups then. RAID controler hardware is better now but HDs still fail, and I'm tempted to get another 300GB Velociraptor to RAID. On the other hand, I may just wait until SSDs are cheaper.
 
Thanks for the info, Chris. Will have to have a think and price up.

Nice bike btw. A VTR if I'm not mistaken? I had one of those but reluctantly sold her a few years ago :( Fantastic machine :)
 
I'm running RAID5 to attempt to mitigate any single drive failure, however I have local backup copies on DVD incase of accidental deletion and a remote backup incase the house burns down! I've been bitten before - not again!
 
I wouldn't advise any critical data to be put on RAID 0 unless you are extremely diligent on a back up regime - I've had two many RAID 0 arrays go at the worse possible time to take that chance with critical data and to be honest I never saw a massive improvement worth the risk anyway
 
:D
baldzone said:
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Nice bike btw. A VTR if I'm not mistaken? I had one of those but reluctantly sold her a few years ago :( Fantastic machine :)
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Yep, '99 VTR 1000. She's sat in my garage with an Optimate to keep the battery in good nic. Had it about 9 months now and a great ride, missing being out on her but I don't do snow and ice on a bike like that.
 
I use a four drive raid 5 formatted to ext2. The file system is fairly indestructible, and mdadm software raid has done an excellent job of fixing itself whenever Ive done something stupid. It also moved from one motherboard to another without flinching. I'm quite happy with it, linux isn't going to kill the array, and if a drive goes down physically the data survives. If I run out of space, easy enough to add another drive. Also means at first glance I look to have a ridiculously large hard drive in the computer.

Raid 0 I was unconvinced by as installing operating systems to them is occasionally difficult, and for the price of two drives id rather have a raptor or ocz ssd.

Raid is not a backup!
 
ChrisLX200 said:
:D

Yep, '99 VTR 1000. She's sat in my garage with an Optimate to keep the battery in good nic. Had it about 9 months now and a great ride, missing being out on her but I don't do snow and ice on a bike like that.
Click to expand...


The trusty optimate never lets ya down! I had a '96 model. Don't blame you for not wanting to take her out in the snow. I keep my sliding around for the off road nowadays :D Just a side note, make sure you replace the cam chain tensioners frequently. I had one fail on me at around 35000 miles. Bent 2 valves and dinked a piston. Cost £200 (for parts) and a few frustrating days off the road. Aside from that never had any trouble with her!



Thanks for the info all :D
 
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if you go RAID 0, make sure you have other backups. You will get a (marginal) performance boost from a Raid 0 setup. But for me the headaches don't offset the gain. I had a RAID 0 setup made from IBM Deathstars, never again...
 
I have a RAID 1 array made up of two 500GB Seagate drives.

It's been running just fine for 2 years now.

This type of array is fairly basic but it does drastically improve performance in high read load situations. However write speed is slightly reduced but not by much.

I like it because it means I can stream 1080p content over the network but still use the PC as though it is idle... With a single drive this just isn't really possible.
 
you need to read up on the RAID types before you can decide whether RAID is worth doing over a single fast disk

wiki link 4tw :)

MW
 
PistolPete said:
I wasn't aware RAID1 gave you better read performance.
Does it alternate the reads between disks or something??
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Ideal RAID1 implementation would have nearly same overal read performance as striping and in case of small files could be actually faster because in striped arrays both drives have to do seek (which is slow) if file didn't fit to single stripe.
While mirrored array can read whole file from disk which can access file faster... and read other file from other disk if there are simultaneous random reads.
And this is where there's lot of variation depending how well optimized read algorithms are, or are they even designed to take benefit of data being available from both disks.


RAID1's weak point is writing where it's slightly slower than single disk but in most uses write performance isn't that big thing... especially considering that RAID0 not only lacks redundancy but even doubles probability of data loss.
(or triples in case of three disk array etc.)
 
JeremyW said:
if you go RAID 0, make sure you have other backups. You will get a (marginal) performance boost from a Raid 0 setup. But for me the headaches don't offset the gain. I had a RAID 0 setup made from IBM Deathstars, never again...
Click to expand...

I had a 4 drive array with Deathstars too, caused me a lot of headaches as they failed one by one. The performance gain is more than marginal - it is significantly faster [almost twice as fast for streaming]. However, as you say, you have to backup the data regularly. You'd be mad to store valuable data on a RAID0 without a full backup.
 
ChrisLX200 said:
I had a 4 drive array with Deathstars too, caused me a lot of headaches as they failed one by one. The performance gain is more than marginal - it is significantly faster [almost twice as fast for streaming]. However, as you say, you have to backup the data regularly. You'd be mad to store valuable data on a RAID0 without a full backup.
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4 drive array with Deathstars, I feel for you man...

Were they from the old 60GXP era ?, we sent out 100s of these at work and they all developed the click of death, cost us 100s of hours in engineering time and created a lot of very unhappy custs. :(

their unreliability was only surpassed by 120Gb Maxtors, which only good use is as a door stop imo :)
 
The first lot were 60GXP, second lot were 120 (not much better, they all failed in the end too). Then I had 4 Seagate 160s, lasted longer but had a couple of failures so took the array down and used them as separate drives for a time. They've all failed now.
Right now I'm playing with 2 seagate 250GB 7200.9 drives (~3 yrs old) and their performance in RAID0 is about the same as a single modern 1TB drive. Just shows how performance has improved over the past few years.
 
PistolPete said:
I wasn't aware RAID1 gave you better read performance.
Does it alternate the reads between disks or something??
Click to expand...

It was quite common that RAID1 was overlooked on this forum as being crap. In reality it is actually a pretty good type of RAID for people that just want to protect against a single drive failure and quite like the idea of having their read operations load balanced across 2 (or more) drives.

Generally the more drives you add to a RAID1 the slower the write performance will get.

It totally depends on your RAID controller obviously.

Some RAID controllers have very bad (i.e. not finished) implementations of RAID1. Whereby only the "first" working drive in the array is used for reads. Or whereby read requests are "broadcasted" to all drives in the array and the first drive to respond wins the race. These implementations are broken and generally if your RAID controller is that bad then I wouldn't trust it with data anyway! It was quite clearly constructed by a couple geeks "that know a thing or two" in a shed in China somewhere.

But all Intel Matrix RAID chipsets (i.e. ICHxR chipsets, where 'x' is a number) have a very good RAID1 implementation whereby read requests are efficiently load balanced across all disks in the array.

See page 10 of http://download.intel.com/design/chipsets/applnots/31085501.pdf
 
Very interesting NathanE, thanks. I did not know that there was any load balancing going on in RAID1 either. Makes me feel better about "wasting" a drive now!
 
with RAID0 i have learn't NOT to keep data such as Pics, documents, videos and music.

I have a RAID0 set up for 2 x 74gb raptors for OS/GAMES/Programms, i reguarly save my Game saves, just incase my raid will ever fail again

i been running the 2 raptors at raid for year and ah half now and the raptors work a treat but are LOUD!
 
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