raid on a home windows pc

[hippoman]

What are the best practices for using raid arrays on home system to provide the best balance between speed, fault tolerance and cost?

I've been thinking about getting a small pair of drives (80-160gb) in a striped pair for operating system (fast access, but either disk goes and I need a reinstall) then a something like 3 x 1tb drives in raid 5 for fault tolerant storage.

Does this sound sensible or am i better with another configuration? 4 x 1tb in striped + mirrored (raid 10)?

cheers in advance...

[Saracen]

There is no best practice, as such. It all depends on what your priorities are and what you're trying to achieve. Different solutions suit different requirements.

[Agent]

I've been thinking about getting a small pair of drives (80-160gb) in a striped pair for operating system (fast access, but either disk goes and I need a reinstall) then a something like 3 x 1tb drives in raid 5 for fault tolerant storage.

This is what I do and I find it works well. I backup the main RAID0 stripe with Acronis every week or so. Worst case means that the OS needs to be restored to a new drive (and the maximum of a weeks loss of anything that has been installed) or a reinstall of the OS.

In both cases though you will need a new / replacement drive to restore the array to. I keep all my data on another non RAID0 setup with other protections in palce (although not RAID5)

[llololloy]

Also, remember as others will tell you and I have learned from experience....
Raid is not a backup solution.
If your psu kills your system, or your controller goes belly up, or a 2nd drive dies whilst doing a rebuild from a previous failure, or any one of other problems, you'll lose all your data.
You need to have an external backup, wether tape, dvd, other hard drive etc.. if your data is precious.

[hippoman]

thanks everyone.

llololloy - totally agree it's not a truely robust solution. I will be looking at a secondary backup solution but I am interested in trying to keep operating system access as free as possible.

Does anyone know if I will see much of a performance increase by using a striped set for os compared to a solitary (fast) sata disk? How about ssd for the os (or even one ssd for os and one for pagefile )??

Is there much advantage in having a separate array for os/programs and one for storage or will I be better off just working with one array for everything.

I usually work with servers where the disk queues can often become a major bottleneck and there can be huge advantages by sharing load over multiple disk queues. I don't have a lot of experience in trying to milk the best performance from home machines but I am open to any advice. My current home pc is best left undescribed and I am looking at building a new one but I want to do it properly.

Is money spent in this area better spent on upgrading other areas of the build?

I'm guessing the answers to these questions are going to be dependant on the roles this home pc is going to do.

I'm looking at building a system based around q6600 and a p35 chip set. (is the ich9r southbridge capable of both raid 0 and 5 at the same time or would I need to be looking at another raid card?) with probably a 8800gt 256mb (19in screen). I would like to see a decent overclock (but want to stick to air).

The pc will likely be asked to do innumerous random things from normal applications and web browsing in vista through a bit of gaming to virtual machines (running a number of workstation and server operating systems but server systems will not be under true working loads). In other worlds I am looking for a bit of an all rounder but I want to try an push for an efficiently powerful machine.

Sorry for all the questions but it seems like hexus forum can provide some valuable advice.

[EnglishLion]

If you're looking at spending enough money for multiple 1tb drives then I would splash out a little extra and get a dedicated PCIe RAID card. They are generally more featured, more stable and easier to replace while retaining your array in the event of RAID controller failure.

I have a 3x 80gb RAID0 second PC (gaming) with no precious data. I can't say it's actually much faster although I don't have any benchmarks to prove it at the moment. For this reason my main PC is just a single SATA2 drive.

[Agent]

If you're looking at spending enough money for multiple 1tb drives then I would splash out a little extra and get a dedicated PCIe RAID card. They are generally more featured, more stable and easier to replace while retaining your array in the event of RAID controller failure.

Intel RAID is pretty dam good, plenty of features and I've not seen any stability issues with it. Even if the controller / motherboard dies, they are forward and backwards compatible in most cases (ie. My RAID array from a P965 board works fine on a P35)

The problem with PCIe cards is the price for a decent model, which can make the cost of RAID rocket

[Eniggly]

I'm using a 4 disk array and I'm absolutely blown away by it.

I got 4 Seagate perpendicular drives and hooked up using the intel matrix raid controller.

Used the first 40 gig of each drive , and then with the remainder I used 2 drives and mirrored them with the other 2.

So the first section is very fast striped raid 0 over the fastest front part of 4 drives. The remainder is raid 10 mirrored of which I backup the first section.

So fast and fault tollerant !

[shaithis]

the best balance between speed, fault tolerance and cost

There is none that I have found. You will have to compromise at least 1 of them.

For me, it was easy, I compromised on cost as I saw performance and fault tolerance as key attributes. Which meant RAID5 with a good raid card.

The on-board RAID controllers normally (always?) use a high amount of CPU cycles compared to a decent add-in card. So you are compromising system performance to keep the price down.

RAID1 vs RAID5: RAID5 will normally have quite an edge on read access, RAID1 will have better write access though. Do you spend more time reading or writing to disk?

RAID arrays are something that are very personal/specific to your needs.....and budget

[Betty_Swallocks]

Custom PC did a test a few years ago on the benefits of having RAID on a home pc and iirc they came to the conclusion that it made very little difference to the performance in real terms and the money spent on the extra hardware would have been better spent on other upgrades that would make a much more significant difference. Faster processor, graphics card etc.

[Agent]

The on-board RAID controllers normally (always?) use a high amount of CPU cycles compared to a decent add-in card. So you are compromising system performance to keep the price down.

This hugely depends on the controller, but the sheer processing power that todays CPU's have is staggering.
It also depends on what kind of RAID you're running. RAID1/0 will use minimal CPU, while RAID 5 will use more.
Either way, its no where near as bad as people make out in my experience

Most common add-in RAID cards are still software based and no better than being integrated. A 'good' add-in RAID card thats hardware based can cost hundreds of pounds.

Intels RAID is very good at what it does and will beat almost all cheap/basic add-in RAID cards in my experience (although that is lacking in the RAID 5 area)

[Agent]

Custom PC did a test a few years ago on the benefits of having RAID on a home pc and iirc they came to the conclusion that it made very little difference to the performance in real terms and the money spent on the extra hardware would have been better spent on other upgrades that would make a much more significant difference. Faster processor, graphics card etc.

A few years ago is huge in terms of computers though. HD's are amazingly cheap compared to a few years back. RAID being integrated into the motherboard is also rapidly becoming standard

Having said that, I tend to agree. Unless you have a specific use for RAID, speed wise it makes little difference in a home PC. RAID1/5 can obviously be used for fault tolerance as well as performance gains - which would just be an added advantage
Although HEXUS isn't full with people with basic machines - we are by and large enthusiasts

[hippoman]

Eniggley - I like the sound of your setup.

What are you using the 4 x 40gb (160gb) striped array for? Operating system? The only down side is you are four times more likely to lose all data on this partition (than a single disk - but much faster).

If you are spliting a physical disk across more than one array do you sacrifice some of the performance advantages? The disks will only have one onboard controller and hence one onboard disk queue so if one array is busy it will affect the performance of the other array.

Might be tempted to try this with 3 x 750gb disks. raid 0 for front 50gb and raid 5 the rest. Should give me 150gb + 1.4tb. Would I be better getting the extra disk and matching the raid 10 of eniggley's setup?

I'm quite tempted to just buy a load of disks and run some benchmarks.

[Agent]

I'm quite tempted to just buy a load of disks and run some benchmarks.

Benchmarks will show an increase even if real world performance isn't mirrored by it -thats what they are designed to do, keep that in mind

[shaithis]

RAID0 normally gives very nice performance but as you stated, it multiplies up the risk of data loss.

I'd personally only run RAID0 on a scratch drive or in a RAID 1+0 scenario (expensive on disks).

[peterb]

Raid 0 gives a theoretically read improvement - but in some cases write pperformance can suffer. Rid 1 gives resiliance in the case of a server (useful if uptime is important) byut as has been hinted at - is NOT a backup substitute!

RAID 5 gives the theoretical performance of RAID 0 with the resilience of RAID1 - RAID 6 even more so - but at the expense of 'redundant' disks that hold the rebuild data if a disk fails.

TBH - I'm not convinced that RAID 0 or 5 is of much practical value in a home set up - althoug it is always fun playing with these things and finding out how they woek.

As for measuring performance, bemchmarks (as Agent says) will tell you pretty much what you wnat to hear - and in actual use, the results will be subjective - if you expect it to be faster, you will think it is.

I do run raid 1 on a server - but I take regular backups as I (almost) suffered total data loss as a result of memory corruption - in the event, I didn't - but that's another story!