storage dillema

[ikorman]

I am running a huge sorage server currently consisting of 40 SCSI drives connected to a 4-channel SCSI RAID controller PLUS a set of 24 more SCSI drives connected via FiberChannel controller and an arbitrated loop switch. Total storage is over 2TB.

As you could imagine, the noise and heat are just unbearable. I am looking to replace the whole SCSI/FC shebang with an IDE RAID solution. My thoughts are:

1. SCSI stuff can be sold for a pretty penny
2. IDE raid will be more portable
3. ................. be cheaper to run
4. ................. be less noisy
5. ................. run cooler

Considerations:

1. Performance is not important
2. Redundance is a must (I am thinking RAID5 with hot-spare)
3. Drives must be connected externally (no room insude the server)
4. Expandability is important
5. Must support large drives (over 200GB)
6. Hot-plug would be nice

Can anyone suggest a solution or point me in the right direction? I heard of IDE over RAID, and serial ATA controllers.

Thanks in advance...

 

[mangyDOG]

Check these guys out http://www.areca.com.tw/index/html/index.htm they have a range of high end raid controllers including 16port SATA Raid6 controllers and of interest to you is a 16 port external SCSI to SATA2 controller.

cheers,
mangyDOG

 

[Mercutio]

Do you actually NEED SAN-type capabilities?

How many people access this storage? What are your I/O loads like?
Do you have any budgetary constraints?

I have a staggering array of SATA/PATA storage on my home network, but I designed for the possibility of multiple simultaneous failures as well.

For basic file sharing aapplications - assuming no need of realtime shared storage, just read-heavy office-type use - I'd think something like a 3ware 8500-8 populated with six 500GB SATA drives in a RAID5 configruation (plus a hot spare) would be just what you'd need.

If write speeds are an issue, RAID10 is the probably the answer. I have less experience with that, but the added expense is rather large. IIRC the 8500-series 3ware cards have a 2TB hard limit per array on a given controller, so a -8 would JUST get you 2TB on 8 drives.

If you're used to paying for FC and SCSI equipment, the price issue will not be THAT big of a deal. There's a premium on big drives, and the controller you'll need to actually BUILD a RAID5 at the 2TB mark isn't exactly cheap. I think you're looking at $2000ish to get going.

Noise will be drastically lower. Heat and power requirements will enter the realm of reasonable. You'll make money back from going SATA on that alone.

And I say that as a going who used to have a 10-disc SCSI array I could hear two rooms away while I was in the shower.

But...
Reliability will probably be an issue. You'll probably want spares on hand. I love my SATA hardware, but I'm not too sure any of it will last as long as SCSI-anything.

You might be better off splitting the load of storage between two less capable machines. In fact, I'd recommend that unless there's some REASON you need 2000GB in a single volume. Four SATA ports = common commodity hardware. .You're probably breaking that 2TB up into multiple volumes, anyway, right? If you really want to have a single addressable 2TB space, you can handle that virtually with dfs or NFS.

 

[Mercutio]

And I typed all that and completely missed the fact that he wants eSATA...

 

[Handruin]

I began looking into eSATA a few weeks back. Tha link has other references to external enclosures and eSATA. However, my storage needs were no where as high as yours, but the idea and parts are similar.

 

[ikorman]

Thanks for all the replies, fellas...

I realize the controller selection is no big deal. If capacity is an issue, I can split up the volume into two parts and have two controllers.

My quest is for an EXTERNAL disk enclosure for about 10 or 12 drives that does not cost a small fortune that supports hot-plug and all the RAID and SATA jazz. Another option is to go with two arrays of 5 (or 6) disk slots if the price is more reasonable. I would not mind having 3 enclosures, if it comes out cheaper. I just dont want to end up with a whole bunch of separate disk boxes.

I figure I can get 250GB drives for now since they are more or less in the financial sweet-spot (about $100). Besides, RAID 5 is more efficient with more of the smaller drives (3 disks of 500GB give only 1000GB of space while 5 disks of 250GB would produce the same results and cheaper). So, I have to have 10 disks total minimum. And that's without a hot-spare.

That brings me to another question: if I have separate disk boxes, can I assign only one hot spare for the whole RAID set if I am on one controller?

My budget is going to be around $3000. That is what I can get for the SCSI stuff. Does that sound reasonable for what I am asking?

 

[ddrueding]

Thanks for all the replies, fellas...

I realize the controller selection is no big deal. If capacity is an issue, I can split up the volume into two parts and have two controllers.

My quest is for an EXTERNAL disk enclosure for about 10 or 12 drives that does not cost a small fortune that supports hot-plug and all the RAID and SATA jazz. Another option is to go with two arrays of 5 (or 6) disk slots if the price is more reasonable. I would not mind having 3 enclosures, if it comes out cheaper. I just dont want to end up with a whole bunch of separate disk boxes.

I figure I can get 250GB drives for now since they are more or less in the financial sweet-spot (about $100). Besides, RAID 5 is more efficient with more of the smaller drives (3 disks of 500GB give only 1000GB of space while 5 disks of 250GB would produce the same results and cheaper). So, I have to have 10 disks total minimum. And that's without a hot-spare.

That brings me to another question: if I have separate disk boxes, can I assign only one hot spare for the whole RAID set if I am on one controller?

My budget is going to be around $3000. That is what I can get for the SCSI stuff. Does that sound reasonable for what I am asking?

It will be cheaper to get a seperate computer with the drives attached, then shared over LAN. eSATA is pretty darn new and there aren't many products out, those that are out cost a pretty penny, and haven't been tested thoughly.

When caluculating the cost of going for more smaller disks in a RAID array, you need to factor in the additional cost of the RAID controllers as well. More drives = more ports. A -16 or -24 port controller is REALLY expensive. An -8 port isn't cheap, and -4port controllers really aren't that bad. No, you won't be able to share a hot-spare accross controllers.

400GB drives are really the sweet-spot in $/GB when cost of ports and power are concerned. If they're going to be in seperate volumes I'd reccomend a few 3Ware Escalade 8506-4LP controllers with 400GB Seagate SATA drives in Supermicro hotswap enclosures in a CoolerMaster Stacker with a 500W power supply and a decent chipset motherboard.

 

[Fushigi]

If 1.8TB usable is adequate, get 2 RAID5 arrays, each with 4 300GB drives. Add 1 cold-spare drive and use hot-swappable enclosures. Buy 2 4-port RAID cards or 1 8-port; whichever you prefer. Over-buy the PSU or buy redundant. Put at least 1GB RAM on the system board; 2GB if you can. It's basically glorified disk cache. 1+ quality Gb Ethernet NICs.

Unless the machine will actually be processing data in addition to managing the disk, the CPU probably won't see much activity. Maybe a single HT-capable Xeon (just to get that 2nd thread capability) or the entry-level AMD dual-core. I wouldn't go overboard, though, unless there's something that you'll be doing that'll tax the CPU. (To be honest, a Celeron would probably do just fine) The disk controllers will manage the disk I/O and RAID calculations; good NICs will off-load most of the IP & Ethernet to the NIC; the CPU is basically left as a traffic cop & cache manager.

One advantage is that each 4-port array can be upgraded/maintained independent of the other.


Or take the easy way out and just buy these whenever you need more space.

 

[ddrueding]

Or take the easy way out and just buy these whenever you need more space.

Seconded. Not the absolute cheapest, but not far from, and really easy to implement, manage, and scale.