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Performance

We benchmarked the performance of the NASes using Western Digital Caviar Black WD5001AALS drives (500 GB) and Intel NASPT. Before the tests we changed the network name, enabled Jumbo Frames, formatted the disk volume, and created a shared folder and a user with full access rights on each NAS.

The junior model comes first. We tested three array types on it: a single disk, a mirror and a striped array.

Positioned as an entry-level model, the DS210j delivers rather high performance: up to 80 MBps for reading and up to 55 MBps for writing. You wouldn’t have got this even from top-end models some three years ago. NAS platforms have been progressing just as desktop PCs do. Besides hardware improvements, firmware optimizations have contributed to this result.

Talking about the different array types, we can note the growth of read speed on the RAID1, which indicates optimizations of this array mode. The RAID0 does not increase performance much. The single disk behaves oddly in the test of two (and, to some extent, four) data threads. We rechecked the results but to the same effect: the HDD must be incompatible with that particular test.

The DS410j goes next. This model supports more array configurations, so there are two diagrams here. The first diagram is for the RAID0 arrays with different number of disks.

The overhead associated with striping makes the 4-disk RAID occasionally slower than the single disk at reading. The 4-disk RAID0 does better at writing, though, but is still not much faster than the single disk. The top read and write speeds are about 60 MBps. Compared with the DS210j, the external SATA controller has a positive effect on the speed of writing, but lowers the speed of reading. Anyway, the speed of 60 MBps is a very high result for an entry-level NAS!

Fault-tolerant arrays load the NAS’s processor more (it is the main processor that has to compute the checksums). Let’s see what performance we have now.

The mirror adds some work for the disk controller, HDDs and internal interfaces, but does not depend much on the processor. This type of RAID often provokes a performance hit at writing whereas reading can even improve if the OS can read alternately from both disks in the mirror. That’s not the case here, though. The DS410j differs from the DS210j and its performance hit is an average 10% relative to the single HDD. That’s not a high price to pay for the increased security of your data.

The more resource-consuming RAID5 increases the load on the NAS’s processor: the 4-disk array is 20% and 10% slower than the single disk at writing and reading, respectively. The gap is even larger if the array consists of 3 disks. On the other hand, the top speeds of 60 MBps (reading) and 45 MBps (writing) are quite enough for most applications.

 
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