- Feb 16, 2010
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Hi, I just purchased some NAS HDD's for replacing our main file server and upgrading our backup servers. We will be moving from 4TB to 12TB storage space.
The drives we selected are the Seagate Iron Wolf 6TB NAS hard disk drives. I received them this morning and was curious to see how they would fare with an ATTO disk benchmark.
What I find interesting is that, if you look at writing speed, there is a very noticeable drop around the 16kB file size. If you put the info in a graph there is a very uniform curve from 0.5kB to 4kB that continues from 64kB to 8MB. The dip in performance occurs at 8kB to 32kB and the 16kB size is slower by far.
Raw write speed data (average of three runs):
4kB: 148.5MB/s
8kB: 140.9 MB/s
16kB: 119.0 MB/s
32kB: 173.6 MB/s
The drive tops out in the region of 220MB/s write speed at file sizes above 128kB.
My question is, why the dip at 16kB? There is no corresponding dip in the read performance. So it doesn't seem to be a system performance issue.
Raw read speed data (average of three runs):
4kB: 214.8 MB/s
8kB: 224.8 MB/s
16kB: 225.4 MB/s
32kB: 225.8 MB/s
So what is the 16k writing bottle neck? It makes no sense to me that 4k files would write 24.7% faster than 16kB files.
The only factor I can think of is sector size, but even then, why would it matter that much?
The drives we selected are the Seagate Iron Wolf 6TB NAS hard disk drives. I received them this morning and was curious to see how they would fare with an ATTO disk benchmark.
What I find interesting is that, if you look at writing speed, there is a very noticeable drop around the 16kB file size. If you put the info in a graph there is a very uniform curve from 0.5kB to 4kB that continues from 64kB to 8MB. The dip in performance occurs at 8kB to 32kB and the 16kB size is slower by far.
Raw write speed data (average of three runs):
4kB: 148.5MB/s
8kB: 140.9 MB/s
16kB: 119.0 MB/s
32kB: 173.6 MB/s
The drive tops out in the region of 220MB/s write speed at file sizes above 128kB.
My question is, why the dip at 16kB? There is no corresponding dip in the read performance. So it doesn't seem to be a system performance issue.
Raw read speed data (average of three runs):
4kB: 214.8 MB/s
8kB: 224.8 MB/s
16kB: 225.4 MB/s
32kB: 225.8 MB/s
So what is the 16k writing bottle neck? It makes no sense to me that 4k files would write 24.7% faster than 16kB files.
The only factor I can think of is sector size, but even then, why would it matter that much?
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