fileserver: raid3/5 question

skanky

skanky

skanky

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im in the process of building a fileserver which will have for data storage (in terms of SATA drives, i have other PATA drives too and a SCSI for a boot drive):
- 1x 250gb samsung SATAII
- 3x 300gb samsung SATAII (identical)
- 1x 300gb maxtor SATAI

my mobo (abit an8u) does a crude form of SATA RAID0/1, only has 4 SATA ports and is currently configured as a 300gb RAID1 array with one maxtor/one samsung drive and the 250gb as standalone. the other 2 samsungs are on order/awaiting delivery. i have 2 options available to me:
- OPTION 1: 3x samsungs as a raid3/5 array and using the maxtor 300gb and the 250gb samsung as standalone drives
- OPTION 2: 4x 300gb in a raid3/5 array and have the 250gb as standalone, that'll cost me more as i'd need a 5 port raid card which'll cost more than the card im eyeing up. also bear in mind that the 4th drive SATAI whereas the others are SATAII and, its a maxtor :)

if ive done the calculations correctly, both options will give me 1150gb useable space but different levels of fault tolerance (600gb vs 900gb). however, im currently leaning towards option 1 and i'm looking at the "3 port XFX Revo64" card as it seems to be available for fairly cheap (£40 mark) however it only does raid3, not raid5 and only has 3 ports: http://www.techreport.com/reviews/2005q4/xfx-revo64/index.x?pg=1

i'd like maximum storage space available to me, but dont particularly see the point in getting another maxtor hdd to raid1 and make that fault tolerant. same goes for the 250gb samsung, whilst its SATAII and all, getting another 250gb drive to make it fault tolerant is a bit pointless in a fileserver if im after space.

i figure i can store the important stuff on the samsung array and non-critical stuff on the others, and stuff i really dont mind losing on the maxtor!!

also, raid3 that much of a bottleneck compared to raid5? apparently that XFX card has a processing unit that does the work with no cpu hit but doesnt support NCQ.

is no NCQ a big loss?

advice, please. :)
 
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NCQ is no loss, in RAID systems having it on tends to be a hinderance rather than a benefit because it tries to second guess what the RAID controller will ask for and usually ends up sending the data in the wrong order. I got a 25% speed increase by turning it off on my RAID5 array.

RAID3 isn't the quickest form of redundant array even with dedicated processing behind it, the parity is stored on a single drive so the write speed of the array is limited by the speed of that drive. The card you're looking at is also PCI so you'll possibly find yourself hitting the 133Mb/s limit on the PCI bus, especially if you have any other devices on there whether they be cards or onboard. If you can live with that then the XFX card isn't that bad, it does some fancy jiggery pokery on the card which makes the array appear as a normal IDE device so you don't need drivers or anything for it.
 
i went for the xfx revo64 in the end. i couldnt justify paying nearer £100 for a decent sata raid5 card, whereas i got the revo64 for what i think is a bargain price of £35.

what do you mean by hitting the 133mb/s limit? i will have quite a few hdds in the system connected by a mix of revo and onboard sata/pata ports and also a pci scsi controller card of some sort running a single crap-ass atlas 10k which i'd like to get rid of at some point.
 
The PCI bus has a bandwidth of 133Mb/s which is shared between all the devices which are attached to it. Depending on the board the PCI bus may support more than just the PCI slots, for example some of the older nForce 3 based boards had the Firewire, LAN and a couple of SATA ports hung off the PCI bus. Modern board tend to use PCIe or direct southbridge connections for these things which takes the bandwidth requirement away from the PCI bus.
 
I've just put in my XFX Revo3 card after the first one was DOA. I had a bunch of 80GB Hitachi drives for free and the card seemed a good way of using some in a machine with no SATA capabilities.

The setup is very straightforward and I used Paragon Disk Manager to copy my old 40GB PATA drive across to the array. Quick to do, easy setup, no drivers so no reconfig of Windows and I got the card when it was on special.

The only downside that I can see is the card doesn't allow any monitoring of the drives so I can't see how hot they are or control their advanced config such as AAM.
 
MikeTimbers: does your syncraid config utility run correctly? i installed the card, set up a raid3 array (3x 300gb) and tried to install the utility from the cd, it seemed to install fine but on reboot i get a "Failed to open device driver" error.

i found this but cant understand, anyone know what language this is in: http://gathering.tweakers.net/forum/list_messages/1138685

edit: i wonder if its because im using server 2003 x64 (the array detects fine in dos and the drive appears correctly in windows) or that ive got a scsi pci card in there, ive noticed that if i have a scsi drive plugged in, i cant enter the bios and the keyboard gets disabled (both usb and ps2), same happens if i boot to dos.

hmm....
 
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fyi the problem seems to be that it doesnt work in server 2003, did a test install of xp, installed the syncraid utility and worked fine!

grr, the manual even says windows 2003 server is compatible! :/
 
For me I'm using XP and the utility works fine although to be honest you're not missing much if it doesn't "work" as it seems to do sod all. No communication with the drives SMART functions so no temperature readings or such like; the only useful function is a green background to the icon showing the status is "good".
 
as it was to be a fileserver, no downtime in not having to reboot to rebuild the array would have been ideal. then again using XP as a simple fileserver wont be too bad, would've preferred to use server 2003 though.
 
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