I have a bunch of lower capacity drives in my backup server - they work fine, but at 1T and 2T, even filled with 24 drives, the capacity is not sufficient for my backup needs.

 

But I can, with my Areca, create RAID0 arrays and hook up a lot more drives.

 

If I want 4T parity, I could create 4x1T=4T RAID0, and 2x2T=4T RAID0 logical drives, and use quite a few more disks than unRAID could recognize separately. If one of the RAID0s failed, I could build onto a 4T drive or another 4T RAID0.

 

But if I want to forgo parity, I could create 4x1T(4T) and 4x2T(8T) and soon 4x3T(12T) logical drives. The backup array is, after all, "protected" by the PROD array. Having the PROD array go down with a 2 drive failures and having the backup server's RAID0s protecting those specific disks also fail at the same time, well, those are odds I could stand. Instead of parity checks, I would do MD5 file verifications on the backup array disks monthly and accomplish a similar result. (I am thinking I like this better than giving up 4T+ for parity on my backup server + the loss of speed in coping files from PROD to backup server).

 

With MB + 2 Areca cards - that would give me 30 physical drive ports.

Adding a port multiplier I'd be up to 46.

And with 2 port multipliers, I'd be up to 62!

 

My limiting factor is drive bays. I have 27 now with 5in3s and 4in3s. I could use a higher density solution. May go back to something like the picture below when the time comes. 10 drives = $0 , not no easy disk swaps. Or add more with the Rosewill solution I posted HERE. Open for suggestions on high volume drive bays!

 

Just thinking right now, but I am liking this concept for a backup server. Let's me use my perfectly good but lower capacity disks for a very long time to come!

 

Thoughts?

 

http://img142.imageshack.us/img142/2092/IMG_4275.jpg[/img]

Not really a bad plan.  Personally I prefer to have even my backup server fault tolerant, but it's certainly true that as long as you're doing frequent confirmations of the data integrity, you could simply replace any failed data from your primary server.    Certainly gives you a nice way to productively use all of your older drives 

 

 

If I were still into the large spindle arrays, I would go with a good SAS controller and go with SAS expanders.

It would be more expensive, but might be better in the long run.

I've never been all that happy with the performance of port multipliers.

 

With the proper SAS expanders you can have two machines hooked up to the sas expanders, and/or you can daisy chain them to grow.

 

Instead of trying to fit 30 drives in chassis, you could divide them up and daisy chain them with SAS expanders.

 

My days of large arrays of spindles is over.

I choose to just go with dense drives. My time in building these monolithic arrays is better spent elsewhere.

 

If I were going down that road, I would bite the bullet with something like these, only I would use the trayless variety of 5x3s.

http://www.pc-pitstop.com/sas_expanders/

I don't like port multipliers because of the severe bandwidth restriction when a lot of drives are simultaneously active.  But in an array without a parity drive, that's not a factor, so they should be fine.

 

Sorry - not port multiplier, SAS expander.

 

I have a good SAS card and 2 SAS expanders.

I don't like port multipliers because of the severe bandwidth restriction when a lot of drives are simultaneously active.  But in an array without a parity drive, that's not a factor, so they should be fine.

 

This is true, and they are plentiful and cost effective.

 

using something like this with internal ports.

http://www.amazon.com/CoolGear%C2%AE-Internal-External-eSATA-Bracket/dp/B004G9V4NI/ref=sr_1_5?ie=UTF8&qid=1427116881&sr=8-5&keywords=4+port+esata

 

or one of the 4 port external controllers (Which aren't very cheap) plus some sans digital towers.

 

i.e.

http://www.newegg.com/Product/Product.aspx?Item=N82E16816111177&cm_re=sans_digital_esata-_-16-111-177-_-Product

http://www.newegg.com/Product/Product.aspx?Item=N82E16816111168&cm_re=sans_digital_esata-_-16-111-168-_-Product

 

A pretty dense array could be set up without limits based on the initial chassis size.

 

These days I tend to compartmentalize my arrays using the HP Micro servers.

 

I may go for the limetech server chassis for the larger server then use the micro servers as backups to the compartmentalized data or by user shares.

After issues in the past I learned the difficulty of dealing with very large servers with umpteen drives in an emergency situation.