Moving to RAID - What Kind of Drive?

[davide101]

Question:
I would like to move from a single hard drive to RAID 1 in order to protect our site against our biggest point of failure. Given the configuration below, what type of hard drive should I get? I want to make sure it's not the bottleneck in my system -- nor get something faster than what I need. I also want the drive to still be adequate when I upgrade to 4gb of RAM.

Current Configuration - $234/mo fully managed
Q6600 processor
2g RAM
74gb 10k RAPTOR
.3 to 1.5 average load, low %iowait until backup time

Raid 1 Options
Dual 120gb 7200rpm SATA 8MB Cache + $20/mo
Dual 74gb 10k RAPTOR 8MB Cache + 60/mo
Dual 73gb 10k SCSI 8MB Cache + $100/mo
Dual 73gb 15k SCSI 16MB Cache + $120/mo

If you have any other feedback, I'd love to hear it. I'm not adept at checking for bottlenecks so if there's something I should look for, please share.

[royo]

Considering the price difference between the 10k and 15rpm configs is so low, I'd go with 15k RPM, which should take your %wait to 0 and be good for quite some time, until you grow and need to move on to RAID10 and more drives.

[nexialys]

check the cache of each drive, this is more important that its speed... some flashed drives now have gigs of ram, making it mostly instant access to cached data... if your HD is used for read-only, this is perfect...

[SEOvB]

You can probably get away with the 10k drives and save the $40 a month.

[Dismounted]

I would like to move from a single hard drive to RAID 1 in order to protect our site against our biggest point of failure.
That would increase the chance of failure ;). RAID 1 is not redundant, and shouldn't even be "RAID" (Redundant Array of Inexpensive (or Independent) Disks). RAID 1 is striping - which theoretically doubles write speed. With this though, you will have 2 points of failure - any single drive dying would bring both drive inaccessible.

[Marco van Herwaarden]

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[royo]

That would increase the chance of failure ;). RAID 1 is not redundant, and shouldn't even be "RAID" (Redundant Array of Inexpensive (or Independent) Disks). RAID 1 is striping - which theoretically doubles write speed. With this though, you will have 2 points of failure - any single drive dying would bring both drive inaccessible.

You're confusing RAID 1 with RAID 0, Dismounted. RAID 0 is a striped set, and RAID 1 is a mirrored set of drives.

[Dismounted]

You're confusing RAID 1 with RAID 0, Dismounted. RAID 0 is a striped set, and RAID 1 is a mirrored set of drives.
Sorry - my bad. Had a late night :p. You are correct.

[superjeff]

if your HD is used for read-only, this is perfect...
And usually "vbulletin's hard disk" are used only to read at the most.. or no?

[davide101]

Here are the options updated with cache info:
Dual 120gb 7200rpm SATA 8MB Cache + $20/mo
Dual 74gb 10k RAPTOR 8MB Cache + 60/mo
Dual 73gb 10k SCSI 8MB Cache + $100/mo
Dual 73gb 15k SCSI 16MB Cache + $120/mo

Is there a point when the hard drives are fast enough that they won't be the bottleneck in a 4gb ram Q6600 system? I'd rather not spend an extra $500 a year to help with a pageloads a month. If it WILL be the bottleneck in six months, I'd rather just upgrade now. I really appreciate all the feedback thus far.

[Dismounted]

You do know that the HDD in any computer is the slowest component. Even the 15k SCSI drive probably couldn't keep up at the rate RAM can transfer data.