We have a set of 6 servers in production for storing some massive databases. Right now they have 280Gb of disk space striped and mirrored across 15K SCSI Drives, our existing database fills them to 213Gb. The new data structure is approximately 1.1x larger than the old.

We need to double the disk space for on of these systems fairly inexpensively. I don't have a "budget" at this time, but let's assume it's under $5K.

We are migrating how we store these databases and we are not buying new servers to migrate too...

The goal is to migrate the data to a temporary database on some temporary storage, delete the old records after confirming that the move was successful, and then move the new records onto the permanent storage.

So, to summarize: 1) We need to temporarily "boost" the amount of capacity in order to migrate the data 2) We don't want to spend lots of money 3) We need to minimize the risk in the middle of transferring data.


I would avoid NAS's. It's just a 'paranoia' thing with me. If you have even 1k to spend, it'd be easy enough to build a basic system (Even new) and load it with 4 or 5 500GB drives, all raided together (My Personal Favourite is Raid-5). In Raid 5 you'd get near 1.5 TB's. If you just did Striping you'd get 2 ~ 2.5 TB's. And then you have a system you can use after the 'project' - either for storage, or for some other application you've been looking at testing.

Remember: A NAS system you have limited control over (which some say would be a good thing). But if you had to somehow manipulate the data that's being stored, a proper computer system would be the way to go, in my opinion.

Good Luck :)

  • 1
    +1; I like this idea, particularly the spare box left over at the end of it. I'd go for RAID 10 rather than 5 though, but that's just me. :) Jun 24 '09 at 23:19
  • In smaller drives (like 500GB) and smaller RAID sets (like 4-5), the odds of a read error go down a lot, which is the reason RAID5 is unreliable for large installations (excluding all performance issues). Since it's a temporary go-between, RAID5 should be alright. Databases over NAS would be way more painful than a local RAID5 ever could be. Jun 25 '09 at 1:23

If performance on the temporary storage isn't a huge deal your best bet would be to get a usb or possible cheap NAS enclosure with a 1TB disk. And dump the temporary data there. Then you have a TB of spare storage whenever you need it for random tasks as well :)

  • It will be WELL under the 5K mark as well. We've got a 2TB Western Digital MyBook Mirror (1TB of usable space), USB interface, and was only a few hundred bucks. With 5k you could build-your-own massive NAS if you needed! Jun 24 '09 at 22:52

Under 5K?

Get a HP Proliant G6 with 8 Disks at 300GB each, 12GB of RAM, 2 Quad Core Procs was about EUR 3-4K - and it takes only 1U

Will give you very good IOPS and you can use it as a real production box later on.

NAS? No thanks, if anything on my site depends on it I wouldn't go with a consumer NAS...

  • There are NAS and NAS :) A 1.1PB NetApp FAS 6000 is a NAS.
    – wazoox
    Jun 25 '09 at 16:02

I would build an opensolaris based box with a supermicro AOC-SAT2-MV8 SATA Controller Card, and some hard drives. This way, if you ever need a place to keep files that are not super heavily utilized, there would be a place for them. A 6-7TB solution like this would put you far under the $1000 mark. It being ZFS means you can grow as you need to.


If these are Linux/Unix boxes, this (or the equivalent for the filesystem in use, if applicable) is often a powerful magic incantation for 'give me more space':

tune2fs -r 100 /dev/whatever

I faced a similar situation with a large Oracle database. We had a Drobo (http://www.drobo.com) on hand (not the network enabled one) so I filled it with disks and connected it to my Mac laptop. I shared the Drobo device out over NFS and copied the data onto it. We did the maintenance required on the production storage and then copied the data to it. Everything went pretty smoothly although it did take quite a while (500GB or so).

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