Hardware RAID

[b0redom]

Hi,
I'm looking to replace a hardware RAID appliance I have (at home). I'm completely software agnostic, using Linux, Solaris, RedHat, Windows, OSX, AIX, and FreeBSD at work.

What's the best OS to create a basic RAID system on? I guess I'm going to need a hardware RAID card - I want RAID-1 or RAID-5, but more importantly I want a notification when a disk starts to go bad.

FreeNAS?
Windows + RAID controller?
OpenSolaris?

What do people recommend?

[alsenior]

the Linux md raid is supposed to be quite good and well developed but obviously limits you to Linux.

for a decent hardware raid adapter look towards either adaptec or 3ware/areca as they seam to have the broadest compatibility range.

for a nas type device i would choose Linux. directhex's project remyth guide was the one i followed and has worked very well for my file server

[b0redom]

TBH I don't care about the underlying OS, they're all pretty much of a muchness. What I really need is to be alerted if a disk is on the way out. My current RAID appliance has intelligent monitoring for disk failures, and I need something similar but preferably in a PC chassis (for speed and volume!)

Does the linux md RAID stuff do this?

[aidanjt]

Yes, mdadm will immediately email you if a faulty disk event crops up, and smartmontools will monitor a HDDs SMART status and, again, email you if the disk(s) it's monitoring is 'unhealthy'. You can also setup snmp if you really want the whole wiz-bang storage feature tri-fecta.

[Lucio]

The best approach to RAID tends to be to get an independant, battery backed up RAID controller card. Worst case scenario, the RAID controller itself dies, you can get an identical replacement card and be up and running again.

And, as with virtually everything PC based, the more you spend, the better you get

[aidanjt]

The best approach to RAID tends to be to get an independant, battery backed up RAID controller card. Worst case scenario, the RAID controller itself dies, you can get an identical replacement card and be up and running again.

And, as with virtually everything PC based, the more you spend, the better you get

Well, no, not really. What do you do when the RAID controller burns out and the manufacturer discontinued the line? For a NAS, software RAID + small UPS is very effective and efficient.

[arthurleung]

Well, no, not really. What do you do when the RAID controller burns out and the manufacturer discontinued the line? For a NAS, software RAID + small UPS is very effective and efficient.

That is why you get RAID card from "real" manufacturer like 3Ware.
You can move RAID array from older card to newer card and the new card can regonize it straight away

[aidanjt]

That's assuming the new cards data structures remain the same, which isn't always the case.

[Moby-Dick]

For home data you can get away with software raid , but if its got anything to do with your livelyhood then

1. Use hardware
2. back it up for heavens sake. RAID isn't a way of avoiding backups !

Even when we run large SANs at work , they still get backed up because you never know what will happen

[aidanjt]

Actually the current state of md is *very* stable, some hardware RAID cards even starting use a stripped down linux with md & mm & i/o driver for storage.

Can't agree more on backups though.

[b0redom]

I run my own business, and it's going to have all the accounts etc on there, so reliability is the key. I'm obviously going to backup to optical media too. Assuming I'm going to use a hardware RAID card, can anyone recommend a good one?

I'll probably go with SATA disks over SCSI if that makes a difference.

Cheers....

[peterb]

Recommending a hardware card is tricky! I use an XFX card bought when Scan were selling them for £10 a pop (I think the original retail price was about £50 or more) Some people will rubbish them - and they are unsiupported (so I bought a spare - just in case) but as they are no longer available, I have just wasted 20 seconds of your time - sorry! They work for me though - under Linux.

Adaptec are (or used to be) the last word in drive controller cards - particularly SCSI, and they have branched out into RAID and SATA. I bought a cheap one (before the XFX) and couldn't get it to play with Fedora Core 6 - last driver they produced for it was for RH9 - so I am a bit prejudiced against them. (But then, a pretty old SCSI card from adaptec worked perfectly - drivers were all embeded in the Kernel)

Looking through thye Scan pages there are a number of what I woulkd regard as 'High end' (ie expensive!) cards that probably do what they say, but (statement of the blindingly obvious) yopu need to ensure that stable drivers are available for them (if they are required) Some may not require drivers - they just appear as a transparent device through BIOS extensions. The problem (I found - with Linux) is that some of the smart monitoring tools (like smartmon) may not be able to interrogate the drive through the controller.

If/when I come to rebuild/upgrade my ssystem, I would probably go for the mdadm solution - in your position I think I would consider building a "pre-production" machine to evaluate for myself how well it performed. If it didn't perform as you hoped, you could then consider adding a dedicated controller. I guess that this will be for a file servver application, so (IMHO) Linux would be an ideal candidate - regardless of whther you intend using Linux or Windows (or Mac) as your main "working" or desktop machine.

(Incidentally, you can set up mdadm on a couple of USB sticks and run them in a RAID configuration to see explore the capabilities before you commit a couple of hard drives.)

[Vimeous]

peterb
I thought the XFX card isn't a full hardware RAID card in the same sense as the others mentioned?

I use a 3Ware HW RAID controller at home (see PC2 in siggie). It supports usual RAID types inc RAID6, SATA, SAS and for up to 8 devices. Battery backup is an option I don't use but if it were for a business I would buy as an extra.
I would have been happy to settle for the Adaptec or LSI Logic alternatives but the 3Ware was better value and critically came with the cables (£20ea+)!
Recent optional upgrade RAID cards (Dell Perc Series) on our work Dell servers are in fact LSI Logic.

Your going to store accounts info which I'd guess isn't huge but critically important.
In this case I'd choose SAS drives for their reliability and warranty.

What kind of box will this be?
Is it a pure storage box?
Will it backup itself or be a source for backup?
Do you want it to do more than serve files?

Regarding OS I'd be tempted to go Windows 2k3 Storage Server.

[aidanjt]

3ware, LSI, and Areca all produce great cards, Areca in particular have fully open kernel drivers and userspace management tools, so they will be present in pretty much any distro you go for. That is if I still haven't convinced you to not waste your money on what's essentially a system on chip RAID OS, for a NAS, or indeed most server boxes, hardware accelerated RAID is pointless, the overhead is negligible.

[peterb]

peterb I thought the XFX card isn't a full hardware RAID card in the same sense as the others mentioned?

Yes - has its own processor - it was a bargain even at the full retail price - shame the processor mfr (Netcell) went bust!

I use a 3Ware HW RAID controller at home (see PC2 in siggie). It supports usual RAID types inc RAID6, SATA, SAS and for up to 8 devices. Battery backup is an option I don't use but if it were for a business I would buy as an extra.

Probably overspecvified for a home based business at the moment - performance won't be critical - resiliance and availability will be. 3ware have a good reputation though.

I would have been happy to settle for the Adaptec or LSI Logic alternatives but the 3Ware was better value and critically came with the cables (£20ea+)!
Recent optional upgrade RAID cards (Dell Perc Series) on our work Dell servers are in fact LSI Logic.

Your going to store accounts info which I'd guess isn't huge but critically important.
In this case I'd choose SAS drives for their reliability and warranty.

Again SAS is (IMHO) way over specified for this. The warranty is immaterial - it doesn't get the data back if the drive fails - far better (again IMHO) to get cheaper drives and take regular backups (which you should be doin g anyway - RAID is not a substitute for backing up!).

What kind of box will this be?
Is it a pure storage box?
Will it backup itself or be a source for backup?
Do you want it to do more than serve files?

Regarding OS I'd be tempted to go Windows 2k3 Storage Server.

As a start up business, a Linux box represents a very cost effective solution - particularly as the OP says he is equally at home with any OS. I'm sure Win 2k3 would do the job equally well - but at greater cost!

I'd still be tempted to evaluate software RAID (madadm) and if that didn't offer satisfactory performance, I'd be looking at something from the likes of 3ware/adaptec/highpoint/areca etc.
(not sure about hihgpoint!)

But I see the XFX is on "Today Only" today at just over £10 - at that price its worth a punt!

We are looking at (I guess) a small business (which I hope will get bigger!) but at the moment there isn't a requirement for a large enterprise type of solution. (and having just seen aidenjt's post - written while I was writing mine - I'd agree - at the moment a high end hardware raid card isn't really justified - at least not unless a software solution is proven to be inadeqyuate.

[Vimeous]

Interesting regards the XFX. It wasn't suitable for us as we initially had 6 drives and will probably be running 8 while the XFX only supports 3.
However that card with 3 Western Digi RE2 drives would be cost effective, fast and the drives should be very reliable.

I agree regarding SAS, it is very expensive for small business. I suggested it because it should be more reliable. Personnally it's not the warranty that matters has much as the drive simply not failing. Much as though drives are ok failing if you have good backups, the rebuild time of a failed RAID array can take your business out of action for at least one day. In big business this can be critical but in small business it can be extremely painful.

Despite all that ,good enterprise-level SATA drives like the RE/RE2 range should be fine.


Any OS is great, it gives massive flexibility.
Linux is exactly as you said, is extremely cost effective, it's also generally reliable.
Despite this I would never recommend a mixed OS environment to a small business. Time is simply too important and in short supply for small businesses to spend any time administering IT functions.

If the desktop PC's are Linux, e.g. Ubuntu or Suse, then a similar OS to run the storage is fine. However if the desktop OS is Win XP I suggest the a similar environment for the storage.
Yes the MS route is more expensive, it's also not necessarily the most intuitive. However if familiarity gets admin tasks done 10% or more faster then extra initial outlay is probably worth it. It also gives a small business much more scope to farm-out their IT support to a third party (to save admin time) as all are likely MS certified first and Linux second (and not necessarily the flavour you've chosen).

I am not saying Linux is a bad choice. It may very well be the best.

Low-end enterprise cards RAID cards like mine cost around £330. Right now peterb is right, its probably overkill. The great thing is they will support any drives you buy so if the cheaper options don't work out you can always add later. Just make sure the motherboard of your storage device will support the future upgrades if they're needed (mines a PCI-E x4 I think which I've got in the second slot of an SLI board).