Performance in Intel IOMeter Sequential Read & Write Patterns
Now that we have already tested the HDD stability when processing random data requests, let’s see how well the drives will cope with the sequential requests. We will use IOMeter for this test and will direct a number of requests with the growing address index (we will requests a set of blocks addressed as 0, 1, 2, 3,…, n). The queue depth is set to 4 requests. Once per minute we change the size of the requests blocks, which allows us to find out if the drive favors (or hates) data blocks of a certain size.
Well, let’s first look at reading:
I would like to draw your attention to… Anyway, you will see it much better on the diagram:
In all our previous Ultra320 SCSI HDDs reviews, the smaller data blocks HDD read speed was always considerably lower with an Ultra320 SCSI controller rather than with an Ultra160 one. Ad here the situation is just the opposite! Moreover, not only the retail drive proved faster with an U320 controller, but even the sample one. Then it is not the tester’s mistake, but the peculiarity of Maxtor HDDs, I assume?
Now let’s check how fast the HDD can read info from its cache buffer, and this way we will be able to measure the maximum data transfer rate via this interface depending on the size of the data block transferred:
Maxtor Atlas 15K @ Adaptec 29160N
Maxtor Atlas 15K @ Adaptec 39320D
It is evident that in case of Adaptec 29160N controller the maximum read speed from the drive is limited by the controller bandwidth (PCI32/33MHz). At the same time the burst read speed with the Adaptec 39320D controller, which supports PCI-X bus standard (but is nevertheless limited by the PC64/66MHz bus in our testbed), appeared beyond 200MB/s. This is amazing!
Maybe this phenomenal interface data transfer rate helps the Maxtor drive to process smaller data blocks in SequentialRead pattern? I believe we will have to undertake a few more experiments before answering this question…
And now let’s check out the SequentialWrite:
Strange as it might seem, but Maxtor drives with U320 SCSI interface perform the writes as fast we they do it with U160 SCSI. Another mystery…
The benchmarks in Sequential Read and Write patterns showed that Maxtor Atlas 15K HDD coped perfectly well with sequential requests of the kind. It is especially successful during reads, it performed at its maximum speed with 4KB data blocks already (and as you know, this is a standard size for the NTFS cluster).