SCSI + RAID

[dribbles]

hi

i was thinking of getting some SCSI drives 2X Hitachi Deathstar 73.6GB hard drives. Ultra Wide 320, 15,000RPM.

would i be getter getting some WD Raptors?

would i be good with a RAID 0 setup or be better going with RAID 0+1/10 (whatever) for added redundancy?

is a RAID setup worth the extra performance?

ive also seen some hot swappable drives, what would i need to set this up?

thanks

[bio]

Ohhh... I get to geek out now!

hi
i was thinking of getting some SCSI drives 2X Hitachi Deathstar 73.6GB hard drives. Ultra Wide 320, 15,000RPM.

Sweet!!

would i be getter getting some WD Raptors?

would i be good with a RAID 0 setup or be better going with RAID 0+1/10 (whatever) for added redundancy?

is a RAID setup worth the extra performance?

I'm not a big fan of Western Digital. I've seen too many of their drives die. Something about the bearings going bad.

You don't have to go SCSI though. In woody (the lovely server you're currently reading this on), I have 4 Seagate Barracuda SATA drives hooked to a 3ware 9500S-4LP SATA raid controler. 3 drives are live in the array, and the 3ware controler is holding the 4th as a self healing spare. One drive dies, it takes over, and the controler rebuilds the array.

Transfer rates are comperal to a SCSI array with 10k drives, but it's much, much cheaper (and supports RAID5... which kicks much butt over 0, 1, and 0+1).

The controler was $350 (I see it's about $315 now) and the 4 80GB drives were $80 each (now $56, damn it!) That gives the server 160GB usable space because of the RAID5 and online spare.

As for performance with RAID... it really depends on what type of RAID you choose.

RAID0 (striping) pretty damn fast. Data is stored on both drives, so when you request it or write it... you read/write to both drives at the same time. It cuts your data transfer rate in half (aprox). Down side... lose one drive, lose all data. This requires at least 2 matching hard drives. Your total drive capacity is the sum of the drives

RAID1 (mirroring) doesn't give you any performance boost, but it does give you redundancy. Of course, this redundancy only does you good if you have another drive handy to put in (to rebuld the array). At least you still have your data. This requires 2 matching hard drives. Total drive capacity is equal to one of the drives.

RAID5 (striping with parity) is the best of both worlds. It requires a minimum of three matching drives. If one drive is lost, your data is still there. Data access is fast like RAID0. You do lose some capacity though. This requires a minimum of 3 matching drives. Capacity is the sum of all drives but one.

RAID10 (mirrored RAID5) is very cool... but takes a special card and probobly isn't worth it for home use. It's two RAID5 arrays that are mirrored and takes a minimum of 6 drives. Capacity is the sum of the drives, divided by two, and minus one drive.

ive also seen some hot swappable drives, what would i need to set this up?

thanks

You'd need to make sure your controler card supported it. Cards that support hot swap are pretty damn spendy. If this is for home use, it's probobly not worth it.

Honestly... I'd go SATA instead of RAID for home use. It's a lot cheaper, it's very damn fast, and the cables take up a lot less room in your case (better air flow).

[dribbles]

RAID5 (striping with parity) is the best of both worlds. It requires a minimum of three matching drives. If one drive is lost, your data is still there. Data access is fast like RAID0. You do lose some capacity though. This requires a minimum of 3 matching drives. Capacity is the sum of all drives but one.

so say u have 3 70Gb drives you have 2X = 140Gb + a parity drive if it does whoopsies?

AND same speed? i thought it was slower because it "checked" the data to ensure integrity?

for sata although fast i thought it was limited by the speed of the drive?

ive had nothing but luck with WD had an IDE 120GB Western Digital for 2.5 years.

only thing i would be limited by if i got a 15k drive (haha) is PCI bus as its slow.

[bio]

so say u have 3 70Gb drives you have 2X = 140Gb + a parity drive if it does whoopsies?

Yes and no.

Yes on the 140GB if you have 3 drives. Nice thing about RAID5... if you have more than 3 drives, you still only loose one worth of capacity.

The parity bit is stored on all 3 drives (as far as I understand it), not on one single drive... so there's no single parity drive.

AND same speed? i thought it was slower because it "checked" the data to ensure integrity?

Not that I'm aware of... though it's possible. Remember... you're reading and writing to all drives at the same time... that improves data troughput dramatically.

for sata although fast i thought it was limited by the speed of the drive?

It also has a lot to do with your controller card (how fast it can process the data). My 3ware is damn fast... and benchmarking tests are what I based that claim on (I did a lot of research when I got it).

ive had nothing but luck with WD had an IDE 120GB Western Digital for 2.5 years.

Then you're lucky. I used to own my own company.. building and selling computers (plus service on those purchased elsewhere). Drives with the highest failure rates were Western Digital, followed by Quantum. I'm a Segate fan... I've never had one fail in the past 10 years, and I've reciently started using Samsung. My samsung is over 2 years old and has had no issues.

only thing i would be limited by if i got a 15k drive (haha) is PCI bus as its slow.

Yeah.... there is that.

Hey...it's your money. I just added my two cents to the question.

[dribbles]

heh. decided to "stuff it" mabey next year or something. reason i looked ar SCSI is WD Raptors cost $250 each delivered in the UK £121.?? total rip off. i refuse to be held to ransom and i dont really need to upgrade my computer. ahh well.