In this study we have selected 15,000rpm drives, the fastest available
rotational hard drives in the market today. Both drives feature
Fibre Channel interfaces and are enclosed in the same 3.5-inch form
factor. Since this analysis will focus more on cost versus IOPS
performance alone, disk capacity is totally irrelevant in this analysis.
To cancel out the advantages (and disadvantages) brought by JBOD
modules from different manufacturers, this analysis will utilize
a generic JBOD module that has the same form factor (2U) and disk
capacity (12 3.5" disks) as the E-Disk®SAN S2F-J from BiTMICRO.
Disk/Module Performance
There has been a dearth of storage hardware literature that tackles
HDD performance as measured in I/Os per second, as most drive manufacturers
publicize disk performance in terms of MB per second (MBps). However,
IOPS statistics are critical in random access applications such
as OLTP and data warehousing, and storage subsystem suppliers post
mission-critical IOPS data in their website. Similarly, BiTMICRO
Networks conducted benchmark tests in November 2003 for its E-Disk®SAN
featuring twelve E-Disk Fibre Channel channels. IOPS results for
a small-block (4KB), sustained random read workloads are posted
in the succeeding table.
To compute for the generic JBOD's performance rating, we multiplied
the 15,000RPM HDD's maximum IOPS rating of 435 with the maximum
number of disks in the enclosure (12). The result, 5,220, is the
theoretical maximum IOPS for small block (4KB) random reads.
Table 3 figures already show a wide disparity in I/O ratings (more
than 1100%) both at the drive and at the enclosure levels. To achieve
the desired performance of 100,000 IOPS, we simply add more enclosures
and drives in the JBOD setup accordingly (Table 4).
Page: 1
| 2 | 3
| NEXT
|
