XP HDD RAID Limitation

[koffiejunkie]

Fair enough but where is the actual data stored? How is data not lost and what if the disk holding the parity info is the one that dies.

The parity is not necessary to read the data if all the data discs are there.

But, like I said, my explanation is very simplistic. The parity is spread across all discs, but is the size of one disc.

 

[koffiejunkie]

was 'Inexpensive' in my era.

Yeah I know, which is strange, since in the early days of Raid the discs were magnificently expensive. And being in a RAID, they're not independant either.

Interdependant is probably a better choice

 

[Perdition]

Well, if the parity disk dies, you wont lose data, cause the data is on the other disks.

You just replace the parity disks, go to your RAID manager and rebuild the array, and the parity is recreated.

if I remember correctly (finished my IT studies way back)

I can remember what RAID stands for though

RAID 5 does not have a dedicated parity disk, parity is stored across all the drives.

 

[koffiejunkie]

The Linux kernel has had Raid-6 for a while now. Same as Raid-5 but with two parity discs, so you can lose two discs. Last time I checked there was one hardware raid card (Areca if I remember correctly) that supported this - I'm really hoping other manufacturer's catch on.

 

[WonderBob]

RAID 5 does not have a dedicated parity disk, parity is stored across all the drives.

correct, I must've got confused by JUGGY's question

anyway, this was never a topic about what a RAID is, so back to the original topic...unfortunately...I have nothing add as far as that goes.

 

[Neo_X]

correct, I must've got confused by JUGGY's question

anyway, this was never a topic about what a RAID is, so back to the original topic...unfortunately...I have nothing add as far as that goes.

Was only off topic for about 50min's...... ;
Looks like i am going to be the Test dummy in this case. I am planning to use Software RAID, as performance wont be an issue(>20MB/s should be fine). I just couldnt get it over my heart/Bank account to shell out another R8k plus for a 12port SATA raid card( if there is such a thing???).

Me wonders if my home PC will be worth a record amount in RSA? total spend on the PC so far is close to R35k

Core2duo 2.4ghz
2GB DDR 800
initially 4x300GB HDD's ( soon to be 12x500's)
Radeon 1900XTX
CM Stacker case
Aopen 700 Watt PSU ( soon to add Aopen 800WATT)


*/ me runs off to install a few security gates

 

[koffiejunkie]

Looks like i am going to be the Test dummy in this case.

Sorry erwintwr, as much as I would love to get my hands dirty with this, I don't have that many spare discs lying around.

I just couldnt get it over my heart/Bank account to shell out another R8k plus for a 12port SATA raid card( if there is such a thing???).

Yes

If you want to be real serious, you can go for 16 ports too.

Me wonders if my home PC will be worth a record amount in RSA? total spend on the PC so far is close to R35k

Dude, you could have had a Mac Pro by now

 

[killadoob]

Me wonders if my home PC will be worth a record amount in RSA? total spend on the PC so far is close to R35k

Core2duo 2.4ghz
2GB DDR 800
initially 4x300GB HDD's ( soon to be 12x500's)
Radeon 1900XTX
CM Stacker case
Aopen 700 Watt PSU ( soon to add Aopen 800WATT)

someone ripped u off badly if that pc cost 35k

damn

 

[Neo_X]

ripped off.... mebe
bought the duo core last year august. let c if memory serves correctly :
Items bought Aug' 06
4 x 300Gb Seagate HDD's : R4000
1 x Duo core CPU : R3000
1 x ATI 1900xtx : R3000
1 x Gigabyte MB(8port onboard SATA): R1000
2 x 1GB DDR2 800 : R1000
1 x CM stacker case : R1200
1 x Aopen 750W PSU : R1500
1 x 19" Aopen monitor :R1500

Items bought Aug '07
12x500Gb Seagate Hdd's : R15360
1 x Aopen 800w PSU : R1500
1 x 4 port Sata HDD controller : R 300
brackets and accesories : R800

Grand total
R34160.00

the 12x500gb's will replace the 3x300's tho... so R30k is more realistic

Sigh....now i know why i drive a crappy car....

 

[proximiti99]

WTF kind of data u backing up man?? U planning 2 save the world some day or what?? IMO data backup for the home shud be max 3 drives ...but thats just me

 

[howardb]

I am currently running XP Pro with 8x 250GB SATA, 4x 250GB PATA and 2x 250GB External HDD's (3.5TB) without any 2.2TB limitation issues - not running in any RAID config though, just JBOD...

 

[repitah]

Reason for the 2TB limit: 32-bit versions of windows cannot boot using a GPT partition table (which allows > 2 TB).

Perhaps RAID 1 the OS then RAID 5 the rest of the system. You may even consider RAID 6 the disks if you're nervous.

I'm not sure if XP will can access volumes > 2TB but I know Server 2003 >=SP1 can.

 

[Neo_X]

Yes , my initial plan is to keep the XP installation on a seperate hdd, and then raidin the other 12. After some googling my future looks a little bit rosier...
http://www.microsoft.com/windowsserversystem/storage/getstorfacts.mspx
.
It seems the 2TB limit is on a single "dynamic" disc, and not on the "dynamic" volumes. The max size of a RAID 5 volume is 62TB... which means my 5.5TB is well within range ... me wonders if this applies to XP as well.,

Next problem will be to "convince" XP to be able to do Software RAID 5. According to Tom's hardware and a few other sites I have to edit a few system files and replace..... sounds risky, but hey.. all in the name of fun.

I will reply once i have manged to get something running.
Thx ppl

PS
Ill dream of 62TB tonite....

 

[repitah]

Storage server isn't going to be cheap. I've played with it in various flavours (and there are a lot of combinations)

 

[Neo_X]

WOOOt its working

YAY. Finally got my RAID 5 to work this weekend. Did take some time tho... Had to reload my OS on a different HDD, and creating the RAID took some time.
http://mybroadband.co.za/photos/showphoto.php?photo=1157&cat=500

1. Install OS ( mine was XP Prof SP2)
2. Install a hex-editor
3. make the following changes:
http://mybroadband.co.za/photos/showphoto.php?photo=1158&cat=500
4. Boot into recovery console and replace the files. I used BART PE to get access to the flies without XP.
5. Boot XPagain. goto (Mycomputer -> Manage -> Disk management).
6. Create a RAID as usual. RAID5 option shoul be there.Note that you need more than 3 HDD's for RAID 5( n + 1 for redundancy). VOILA


One thing that caught me. It seems to create the RAID and parity etc takes some time. For my 5TB it took about 8 hours with an action called regenrating (with a quick format...)
Another thing to remember : Since you are working of edited XP files, there is a good chance that a future service pack/ Automatic update can reverse your changes and make your RAID probably inaccesible. be careful.

good luck.

 

[bdt]

Next problem will be to "convince" XP to be able to do Software RAID 5. According to Tom's hardware and a few other sites I have to edit a few system files and replace..... sounds risky, but hey.. all in the name of fun.

I've done that Tom's Hardware thing, it works - of course, throughput ain't all THAT great but you said you're not worried about that ..maybe look at doing gigabit LAN to counter for that?

But, and I'm sure you know this, XP is a desktop OS (and not hugely reliable at that either!) , 2003 in the 'doze-world would be a better way to go. That said, you have other options: FreeNAS installs to a <=32MEG CF card and does a bang-up job; it's a REAL network storage OS that has a micro footprint and explicitly does software RAID-5. Also, if you're feeling strong, consider Openfiler, an optimised Linux SAN/NAS distro that also handle software RAID - but goes that one extra to RAID-6 ..which really CAN be your friend - and on the number of disks you have, losing 2 to parity is, percentage-wise, a small enough hit for it to be well worth considering!

Oh, and as to whether you can get a 12/16 port SATA RAID card, I Promise that you can!

 

[koffiejunkie]

Since you are working of edited XP files, there is a good chance that a future service pack/ Automatic update can reverse your changes and make your RAID probably inaccesible. be careful.

Which is why, if you're willing to spend the money on 12 hard discs, you can just as well spend an extra 3k and get a decent hardware raid card, so that even if your windows gets wiped, you can still access your data (just pop in a Knoppix CD and off you go!)