Best SCSI Setup

D

DoMeHardR

Limp Gawd
Joined
Oct 16, 2002
Messages
227
First off, I am not very well educated when it comes to storage so sorry if my ideas seem bad or incorrect. I was wondering what you guys would recommend for a SCSI setup. It is for a new server for a internet insurance site. People log in to view insurance certificates and generate reports. Now for space wise we really only need maybe 10 gigs of space (with massive future growth considered) because most of the field are bool. I was thinking of getting 2x 18GB 15k u320 drivers and doing a raid 1 on them. This site is very DB intensive and the major bottleneck seems to be the disks. The report generation takes a while to index the thousands of records.

My question is what are the best drives and controller for this. Money isn't really a concern as long as it is the fastest possible with redundency. Also, any other recommendations for the drive setup? (having seperate OS drive, different raid, etc)

Thanks.
 
Here is a common setup I see for speed and redundancy.

2 x 18gb 15k drives Raid 1 array - Operating System
3 or more 18gb 15k drives Raid 5 array - Database

This would give you plenty of speed and data redundancy. The more drives in the Raid 5 array the faster it will be.
 
Larger hard drives are faster. The fastest SCSI HD is currently the Fujitsu MAS3735NP, 73 GB. (The Fujitsu MAU, soon to be released, will supersede it. It is 143 GB.)

Four 73 GB MAS drives in RAID 10 would be extremely fast (I forget which is better, striped mirrored or mirrored striped). You would need a SCSI controller capable of this (I prefer Adaptec but haven't looked into RAID 10 myself), and a system that could handle some 140 MB/sec sustained (and greater burst) to the array. That is to say, slapping this on PCI would be counterproductive. You'd need a server board with PCI-X.
 
Would a RAID 5 have an advantage over RAID 1 in indexing records faster to produce a report? Also, putting the OS on different drives and different channel (right?)from the DB, would make it a bit quicker?

So I'm guessing I need a 2 channel RAID 1 and 5 controller. I was looking at Adaptec SCSI RAID 2200S . This card has 64MB of cache. Is this enough? I have seen ones with a lot more. Does it make that much difference?

Also, which brand of drives would you guys recommend?
 
ambit is correct that RAID 5 arrays are slower at writes than RAID1 would be. This is because a write in a RAID 5 volume requires a read of the entire stripe of data, an XOR operation of this data with the new data to be written, and finally committing this new data and XOR to the disk as a write. RAID 5 performance is very dependent on the controller you are using. For U320 SCSI, I like Ambit's suggestion -- it is the fastest reasonably affordable two channel U320 RAID controller that you can buy currently.

Also, keep in mind aug1516's statement that more drives in a RAID 5 volume will increase performance (at least on reads, which seem to be more important for your particular use). Adding more drives to a RAID 1 volume will increase redundancy, but not increase speed. (This increase, of course, is limted by the IO processor on the adapter and the bandwidth of both the SCSI bus and PCI bus)
 
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