Storage array

[Jared555]

I am wanting to set up an expandable storage array for backups and downloads. (The only thing it might do other than that is eventually store some mythtv stuff but I would probably set it up so it wouldn't be storing it to that array real time).

I will most likely be using linux with EVMS so I can expand the array later (supposedly it allows you to expand RAID 5 arrays). The array will probably start at 500GB (I might be able to go to 1000GB with 250GB drives)

I am trying to decide between a few main configurations (and if there are other good choices I will look at them also)..... Price is a major issue (RAID50, 10, etc. loose too many drives for me)

1. Pure RAID 5 of 250GB drives: Cheap, but lots of drives
2. Pure RAID 5 of 500GB drives: A lot more expensive, but less drives

Then some of the... interesting(insane?)... configurations:
3. Starting with a RAID5 array made up of 3 250GB drives, then when I need more space forming a RAID55 array built out of the RAID5 arrays, or if the 500GB drives have dropped in price, creating a 1TB RAID5 array built out of a 500GB RAID5 array and two 500GB hard drives.

That would avoid the initial expense of creating a RAID5 array out of 500GB drives...


4. Starting with a RAID05 array (a raid 5 array with raid 0 elements) and then if/when the price of 500GB drives drops instead of adding RAID0 arrays of 250GB drives just add 500GB drives.

Sort of like #1, there would be a lot of drives, but it would be pretty cheap to do. Kind of worries me on reliability but it doesn't seem too much worse than RAID5 by itself.

5. Creating separate arrays for 250GB, 500GB, etc. drives and then using spanning to connect the arrays.

Performance hit because not all drives are in the array but allows any size drives to be used. Some files may load extremely fast but others would be slower depending on # of drives in the array it is reading from.

 

[Jeepson33s]

if you want to wait until tomarrow, i will ask some of the guys in my RAID team if they can help you out. They are the cream of the crop when it comes to answering these questions. IMHO, i think that 5 will be your best bet. Just span the array when you add more drives.

 

[Jared555]

Ok. I can increase the size until I change what size drives I am buying then I would have to either replace everything or only use part of the drives. (with RAID5)

Other than being able to use different sized drives, I was reading supposedly RAID50/05 give a speed boost (the reason most people use it).

Also, I looked more and the cost of RAID50 vs 05 wouldn't be much worse if I only used two RAID5 arrays initially.

The other challenge will be as drives get added fitting them in a case, but once that becomes a problem (it will not be for a year or two probably) I might go to external sata enclosures (until I run out of the ability to add external ports).

The best part is if you want to add 2-3+ drives to a software raid5 array it has to be done one at a time, so it would probably take a week.