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Atto/iStoragePro RAID Conclusions
Related: backup, Other World Computing, RAID, RAID-5, RAID-6, storage
I liked the iStoragePro iT8SAE a great deal, so I bought one.
I have integrated the iStoragePro iT8SAE into into my system workflow, so that I can offload and archive older and less frequently accessed material onto it, thus freeing up enough space to allow an all-SSD system for internal use in the drive bays of my Mac Pro (soon). External backups should still be made in any case, and stored elsewhere, since all hardware in one location is at risk together.
Update Nov 30 2010: be sure to read the Atto fan controller noise problem. This problem make me retract my recommendation for the Atto R380 RAID card unless you are deaf or wear ear plugs.
Putting a storage system together
Here’s what you need (see this handy shopping cart at OWC):
- iStoragePro iT8 SAE
- Atto R380 RAID card
- At least one cable (two recommended for best performance);
- The hard drives. I recommend getting nine (9) drives so you have a cold spare as well.
My recommendation is RAID-6 with 7 drives plus one hot spare, and one cold spare (9 drives total).
RAID card is crucial
Of great importance is the RAID card, because it determines what features and performance are available, and the software that is used to do so. While the Atto R380 card is a great choice, the fact that it throttles performance in the 6-8 drive range makes me think that the R680 would be a better choice (twice the bandwidth as well as SATA 6G support).
More space needed?
A single RAID card can control the iT8SAE and additional units daisy-chained in series. Just cable it up and go.
Recommended RAID setup
Reliability is especially important for large data sets, e.g. video and photography, because the restore process is a day-long event, and in most cases, that kind of data can never be recreated.
My advice for most users is a RAID-6 with one hot spare as making the most sense, because it yields 10TB of storage from 16TB of drives (8 drives), while providing exceptional performance and a high level of fault tolerance.
Note that RAID-6 does not remove the need for backups; physical hazards still exist, such as a power surge, failure of a power supply, theft, fire, flood, etc; all can destroy the RAID. Physical hazards aside, RAID-6 ensures that data loss is a very low probability event.
For more modest storage needs or other Macs
For RAID-5 in a plug and play form factor, choose the OWC QX2 and the NewerTech 6G card. That combination won’t perform at the same level, but it’s still very speedy with eSATA, and costs less. The OWC QX2 can also be used on any Mac or PC with Firewire 800 or USB 2, no special hardware card is needed, keeping the cost down.
Room for growth
To offload data from my main volume, I’m looking for:
- High reliability;
- Fast access;
- Convenience of one large volume.
These needs are not met by a single 2TB external drive; performance is low, reliability is single-drive, and data must be split across volumes. They could be met by the OWC QX2 in RAID-5 mode, which offers 6TB of capacity in RAID-5 mode, albeit at very fast, but somewhat lower performance.
Were I to move to the iStoragePro — since my storage needs should remain under 3TB through 2011, I’d insert five (5) drives for starters: 4 drives for the RAID-6, and one hot spare, a lot of redundancy, but worry free in terms of drive failure.. That would yield 4TB of storage, enough for some time to come. The other 3 bays could be used for other volumes, perhaps a RAID-5 backup. Then again, fully populating the unit means I can set-and-forget, and also enjoy the outstanding performance.
