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View Full Version : HD setup suggestions please (long read)


Thuleman
11-06-2004, 01:26 AM
Currently I am pretty frustrated, not sure where to start, so here is my current setup:

4x 75GB IBM Deskstar ATA100 7200rpm
Two of those are single master, two are connected to a Promise ATA100 raid (raid0).
I also have 4x 250GB Lacie FireWire 800 drives connected to that system, a well as a Promise RM8000 DAS loaded with 8x 250GB IBM (raid5).
This is at work.

Most of my time I work on analyzing satellite imagery, so there is not a whole lot of random access stuff going on, but rather large files are being read and written, often large temporary file space is occupied by the application used.

The application supports hyper-threading, or at least multi-threading, so I can spawn a few different processes to work on this simultaniously. However, I feel that besides CPU cycles (one can never have too many of those) disk access is slowing me down.

My RM8000 system is for data delivery, so I can't use those drives as "production" space, that array is exclusivly for the finished products.

Ultimately what I envision is that I have multiple fast disks I can read source data from, and multiple fast disks (different from the source data) that I can write intermediate data to before the final product is moved to the RM8000. I also need a drive or drives to hold the OS (Win2k), OS pagefile, applications, and scratch disk for applications.

SCSI is probably the way to go, but there are two things that make SCSI less attractive, one of which is obviously the price, the other is that the drives are small in comparison to SATA drives.

I could probably get away with buying a bunch of disks, but I do have some concerns. There is the physical limitation of how many disks ordinaty cases can hold. There are neat cases (i.e. Supermicro) with built-in hot swapable bays and such, but hot swapping is not a requirement, and the problem I see with those cases is that the drives can't be mounted in a way to reduce noise.

I would very much like to keep the noise down.

So, here are the questions:

If I would like to have three continuous read operations, three continuous write operations, application swap space, and OS overhead going, what would a recommended HD setup be to accomodate all this reading and writing? As in multiple single Raptors, one huge array, multiple dual disk arrays, some such?

There is also the issue of housing all these drives, and associated noise. I would very much like to keep the noise down, perhaps suspend the 3.5in drives DIY-style in 5.25in bays, I haven't seen many cases that have that many 5.25in bays. (asked in the case forum already).

Multiple RAID controllers would not be an issue, I don't really need the PCI slots for anything anyway.

Thanks for reading through this, and for your suggestions.

Edit: are there any compelling reasons to not just mount all those drives on a big sheet of plywood?

budec
11-11-2004, 03:22 PM
What's your budget?

You could get 2 RAID cards and do this:


Raid Card 1:
Raid 1: Raid 0 (2x100)
Raid 2: Raid 0 (2x100)

Raid Card 2:
Raid 3: Raid 0 (2x100)
Raid 4: Raid 1 (2x160)


every night just have an automatic job that backs the data up from Raid 1-3 to Raid 4.

zandor
11-12-2004, 07:39 PM
You could always hop on eBay and get a bunch of used Fibre Channel stuff. You'll beed a raid controller of course (that can be expensive), but you can put the FC-AL cabinets in a different room. Even copper is good for 30 meters or something like that.
Another option is to get a couple cheap dual CPU machines (say Athlon MP board w/ a single CPU... the raid contoller will do most of the work) so you get 64-bit slots, and just set up a gigabit network with remote file servers. Then just toss in a 64-bit gigabit nic and a 3ware card (they make them w/ at least 8 SATA ports & raid 0, 1, 1+0, and 5 support) and load the boxen up with SATA drives. If you really want to have fun get a dual or quad port gigabit nic for your workstation so you can have a dedicated gigabit link to each file server. So basically 100MB/s each way to each file server. If it works as well as I think it should you could strip your workstation down to say 2 disks (1 for OS (and probably apps) and one for swap and "junk")

unhappy_mage
11-12-2004, 11:04 PM
for something cheaper, look at 3ware's 4way card (tee hee) and use in 0+1 mode with 4 7200.8's. They just came out, they should be on newegg soon. That's more like $1200 than the $2500 for a seperate machine. You could buy the 8way version (there's also a 12-way!) but raid5 on the larger controllers is a good thing.

With just 4 disks, it's probably ok to just use the internal 3.5" bays to store the hard drives; with 8+ you really need the cooling.

edit: zandor: old FC? quiet? wow. I'll believe it when I see it.