Raid help

[pctweak]

I am somewhat new to raid 5. I am thinking of purchasing a PowerEdge 1800 with raid 5. If I only have 3 hard drives I will have disck stripping with parity? So if one drive fails I can swap out with a new drive? Will windows 2000 still be running if this happens. Should I get 4 drives? I guess any info you could tell me would be great.

TOTAL $1152.00

Module PowerEdge 1800

Intel® Xeon™ processor at 2.8GHz/1MB Cache, 800MHz FSB

FREE QUADRUPLE UPGRADE to 2GB DDR2 400MHz 2 Single Ranked DIMMs

Primary Controller FREE! CERC 6-Channel SATA RAID Controller

Onboard NIC

Hard Drive Configuration
Add-in SATA card RAID 5, Minimum 3 drives required

3Yr BRONZE Support, Next Business Day Onsite

Hard Drive's

3 - 40GB 7200 RPM SATA Hard Drive

 

[trainmaster77]

how often have you heard of drives failing? it doesnt happen often enough to worry about it. i would get 4 drives and raid0 them. as a matter of fact ..for as long as i can remember ive never had a drive go bad... just get a good power backup from apc and youre straight.

those 40 gb 7200 rpm sata drives arent enough money to justify wasting one drive just for backup ... raid all 4 of them.

 

[pctweak]

how often have you heard of drives failing? it doesnt happen often enough to worry about it. i would get 4 drives and raid0 them. as a matter of fact ..for as long as i can remember ive never had a drive go bad... just get a good power backup from apc and youre straight.

those 40 gb 7200 rpm sata drives arent enough money to justify wasting one drive just for backup ... raid all 4 of them.

[font=&quot]
True, but I need more then a tape backup for what the server is being used for. I will sacrifice some speed for redundancy and insurance we do not loose data.[/font]

 

[trainmaster77]

[font=&quot]
True, but I need more then a tape backup for what the server is being used for. I will sacrifice some speed for redundancy and insurance we do not loose data.[/font]

how much are those drives? id buy 2 more haha raid0 4 of them and use the fifth for the backup. i think you can do it that way. I dunno, ive never used that many hard drives haha.

 

[LordOfLA]

for raid 5 to work you need 1 drive as parity and one drive to mirror the other
so to have a one drive hotswap raid 5 you need 3 drives. after that increment by 2 each time you neede to add another drive.

 

[Zedric]

for raid 5 to work you need 1 drive as parity and one drive to mirror the other
so to have a one drive hotswap raid 5 you need 3 drives. after that increment by 2 each time you neede to add another drive.

Huh? RAID 5 doesn't use parity drives, that's RAID 3. And what mirror? Increment by two? Why?

RAID 5 has distributed parity blocks.

RAID 5:
======================
[b] P[/b] = Parity information

Disk 1	Disk 2	Disk 3
------	------	------
|  [b]P[/b] |	|  1 |	|  2 |
|  3 |	|  [b]P[/b] |	|  4 |
|  5 |	|  6 |	|  [b]P[/b] |
|  [b]P[/b] |	|  7 |	|  8 |
|  9 |	|  [b]P[/b] |	| 10 |
| 11 |	| 12 |	|  [b]P[/b] |
|  [b]P[/b] |	| 13 |	| 14 |
| 15 |	|  [b]P[/b] |	| 16 |
------	------	------

RAID 5 needs a minimum of 3 disks. After that you can add more disks if you wish. The best price/performance ratio is at about 4-6 disks. So if you can afford it, get 4. And RAID 0 isn't an alternative. RAID 0 should only be used for temporary and non-critical storage. RAID 5 is redundant (for single disk failures), but still faster than RAID 1 (mirroring). The total available storage space of a RAID 5 array is the disk size times the number of disks minus one (C*(N-1), C is capacity, N is # of drives).

 

[pctweak]

thanks I think I will go for raid 5 with 4 hard drives. Dell rips you off for that 4th 40gig and they make you buy atleaset 3, so I will see if I can order the same hard dirve from newegg of something.

If I have 4 - 40gigs that will give me 120 gigs of space. That should last about 20 years for what we need it for, perfect!! thanks