SAS support - SATA is much too slow

[dkvello]

I user these NAS-boxes for doing Full & Incremental Acronis-images of servers. Problem is that SATA/SATAII has terrible performance when it comes to parallell I/O & Random I/O.

If I do more than one Server-image to the NAS at a time, the performance drops drastically.

Since SATAII and SAS share physical connections and there are combined SAS/SATA controllers out there, being able to put 4 * 300GB 15K SAS drives in there would be just perfect.

Just around 1TB of RAID5 is good enough (larger SAS-drives will come) for our purpose. What we really need is an small NAS that can handle the I/O demands. This would mean a good TOE implementation on the GBit Ethernet as well.

Throw in an iSCSI Initiator (could be just a SW implementation) and it would make my year.

[Gomjaba]

Sounds like a good idea .. won't be a cheap SOHO option anymore though .. but yes, at least you could decide

[dkvello]

Well, true. but I test a lot of combined SAS/SATA controllers/Chips from f.eks. LSI, and it wont bump the price of a CS/RS 406/406e more than 7% (if You deduct the cost of the existing SATAII controller).

If implemented correctly, it could give you the option of useing either SAS or SATA disks and even give the option of mixing SAS and SATA in the cabinet, but not in the same RAID/Volume.

Putting the XOR engine in HW will be of great benefit. They could even sell a Battery-back-up cache option for those that need the extra performance and security.

Personally, I would buy one for my home
I use Synology now because it's closest to what I need at a good price.
The alternatives today that use better RAID/SAS technology costs $3000 and upward.

There is a huge gap inbetween the cheapest $100-$500 NAS units from Synology (and others) and the $3000-$10000 NAS options from Dell/HP/IBM/Tandberg etc.

Sounds like a good idea .. won't be a cheap SOHO option anymore though .. but yes, at least you could decide

[SydneyGuy]

I don't think faster drives is going to give you what you want. The bottleneck in the performance of these devices is the software RAID. I'd rather see hardware RAID implemented before a change to SAS. That would see a boost in performance as well as still being able to use readily available high capacity drives.

[dkvello]

Well, I've used HW RAID controllers for SATA, and although that alleviates the XOR performance problems (some atleast) it still is SATA with all its short-commings when it comes to performance.
As said earlier, SATA & SAS shares physical connectors. There are plenty of HW RAID HBA's that support SAS & SATA.

I have tested $100.000 implementations of an IBM DS4100 and it still performs terrible because it is SATA. 4 Local SAS-drives with a MegaRAID controller performed better in random read/write (Cache performance is irrelevant, only actual disk I/O is).

I don't think faster drives is going to give you what you want. The bottleneck in the performance of these devices is the software RAID. I'd rather see hardware RAID implemented before a change to SAS. That would see a boost in performance as well as still being able to use readily available high capacity drives.