Revo 64 RAID card and RAID options

[peterb]

I bought the RVO 64 RAID card a couple of months ago when Scan were selling them off, and now thinking about using it. The system it may go into is a linux (FC6) based system running a web server (about 3000 hits/month) and filke server. It is AMD socket A based and only has IDE drive ports.

While I back up critical data, RAID 1 would give some redundacy and peace of mind, and the Revo card, while pretty cheap had a good review on here on Hexus in terms of performance, but missed out one (to my mind) crucial aspect of performance, and that was array rebuilding and reliability, and some subsequent comments hinted at potential problems in this area.

So I have two options - use the card's own RAID capability to implement the RAID 1 array or

Use the card as a straightforward SATA drive controller and implement RAID1 as a software solution using FC6 built in capability.

Option 1 has the advantage of simplicity of implementation - set up the array and then migrate the data across to it. The disadvantages are the uncertainty of the performance/reliability in rebuilding the array if a drive fails, and the fact that I am probably tied to that controller - there is no guarantee that the array would migrate to another controller if the controller itself failed. (and a replacement controller is probably unobtainable)

Option 2 has the advantage of hardware independence - as it is implemented in software, provided I remain with teh same OS, the data is available, and the RAID software in FC6 is pretty much tried and tested. The disadvantages are increased complexity in setting up and migrating the data, and a possible performance hit, which isn't of great concern.

So I have pretty much talked myself into the second option - but

has anyone had any experience with these cards, particularly in the case of array rebuilding and reliability?

Any other comments on the above analysis?

(I realise that RAID does not remove the requirment to take backups, and also includes a requirment to monitor disk health on a regular basis to detect a failing disk so a failed disk does not remain hidden by the array - until the remaining one fails)

[arthurleung]

Consider the Revo64 is a very old architecture, and the company who made it (Netcell) have already folded, there is highly unlikely there will be any driver support for the card in the future. If you update your kernel or switch OS you might find yourself unable to pull data off that card. Even worse XFX seems to have stopped producing these cards and you might not find a replacement if it ever fails.

The Revo64 is a PCI32/33 Card which tops out at 133MB/s (Practical limit is about 100MB/s). On a Socket A system without native SATA support you will not see any difference, but if you ever migrate it to a new system, the native SATA ports (connected directly to the chipset), you will see significantly higher STR on Option 2;

[alsenior]

has anyone had any experience with these cards, particularly in the case of array rebuilding and reliability?

i have 2 of these cards in active service one in my main computer for about 5 months and had to rebuild the array a few days ago due to a drive dropping out and it is pretty fast ~2 1/2 hours to rebuild a 250gb raid 3 array i have seen worse.

the card is a fully hardware card so it offloads all processing from the cpu so in this case it way be better to use the card.

on the driver front the card does not need any drivers. it is shown to the system as a intel ide controller and the array is shown as one disk.the only problem is that the monitoring utility is not available in Linux so if a drive fails you will only know about it on reboot.

[peterb]

Thank you. Pretty much convinced that optiuon 2 (software implementation) is the way to go, just use the card as a SATA controller. The Software RAID implementation is unlikely to change as the Kernel changes so it should be more futureproof if/when I moved to a mobo with an embedded SATA controller.

I see Scan are selling them again today - £10.00 so it might be worth getting another one as a spare!

[arthurleung]

i have 2 of these cards in active service one in my main computer for about 5 months and had to rebuild the array a few days ago due to a drive dropping out and it is pretty fast ~2 1/2 hours to rebuild a 250gb raid 3 array i have seen worse.

the card is a fully hardware card so it offloads all processing from the cpu so in this case it way be better to use the card.

on the driver front the card does not need any drivers. it is shown to the system as a intel ide controller and the array is shown as one disk.the only problem is that the monitoring utility is not available in Linux so if a drive fails you will only know about it on reboot.

Back then I was very tempted to buy one of those cards, I do agree they have very good performance consider they're about a tenner. Your rebuild speed is about 27.7MB/s so it is on par with most hardware IDE RAID controllers (e.g. 3Ware 7500/7506 series, LSI Megaraid i4)

Linux seems have a very good RAID5 implementation, I heard people having speed >100MB/s on RAID5 array (not possible on Socket A's PCI bus though)


http://forums.hexus.net/showthread.php?t=78203&page=3
The driver issue is a bit fuzzy on linux and as the company had folded. Check that thread and there seems to be loads of answer for you regarding to that card.

P.S. My 4x300G RAID5 on 3ware card rebuilds at 65MB/s FYI. Crappy SIL3114 does RAID5 at 3MB/s on the other hand.