X-bit labs

400GB Hard Disk Drives in RAID 0, RAID 5 and RAID 10 Arrays: Performance Analysis (page 6)

Category: Storage

by Nikita Nikolaichev

[ 02/23/2007 | 08:17 AM ]

Intel IOMeter Sequential Read & Write Patterns

These patterns help investigate the performance of the controller and HDDs at sequential reading and writing. IOMeter is sending a stream of read/write requests with a queue depth of 4 to the array. Each minute the size of the requested data block is changed so that we could see the dependence of the sequential read/write speed on the data block size.

So, we’ve got an opportunity to give some praise to the Seagate drive. Without a doubt, it is superior in this pattern. The Hitachi team has the lowest results because it is the least dense of all the HDD models included into this test.

The maximum read speed is reached sooner by the RAID5 arrays than by the RAID0 ones – on 4KB and 8KB data blocks, respectively. Note the way the WD4000KS-based array is reaching its max speed – its graph is smoother than the others.

But the WD4000KS model does much better in a RAID10 array and outperforms all other HDDs. Let’s see now what we have at writing.

The WD4000KS is best in this test. Its large cache and high areal density put it ahead of its opponents.

We’ve got another fit of “sea sickness” in RAID5 mode. None of the arrays could draw a flat graph. The controller’s operation algorithms in RAID5 mode seem to be exceedingly sensitive to the size of the data block and the HDDs’ segmentation at deferred writing.

Curiously, the Maxtor-based array did well in this test!

The WD4000KS is again among the leaders in RAID10 mode.