Have a new JackRabbit-S unit in the lab, 5.5TB (16 drive unit, 2 allocated for OS, 1 for hot spare, RAID6 built out of remaining 13 drives).
and dbench output
a really simple script:
#!/bin/bash sync echo -n "start at " date dd if=/dev/zero of=/local/big.file bs=134217728 count=100 oflag=direct sync echo -n "stop at " date
and its results
Hmmm…. on a 16 GB machine, even with the sync’s I am worried about cache. Fine. Lets blow cache away.
Changing the 100 to 1000 there (130GB). Somewhat of an understatement, but this is well outside of cache.
Thats 699MB/s to local file system way outside of cache. Not bad.
With 13 disks in a RAID6, 11 are available for storage (5.5TB as these are 500 GB units). At about 70 MB/s native speed, we have a “theoretical” native sustained speed of 770MB/s. So this controller was driving these disks at about 90.8% efficiency.
Hmmm… where’d my other 9.2% go? Oh yeah, little matter of OS and related.
Not bad for a little unit. Not bad at all.
Update: So here is 1.3TB of file …
612 MB/s to write 1.3TB of a single file. RAID cache is under 0.2% of the size of this file. System RAM is about 1% the size of this file.
Not bad at all …
BTW: this is 1.0737e+13 bits (10.7 Tb, 10.7 TERA-bits), in 2192 seconds. This puts it at 4.9 Gb/s of IO speed.