USB3 RAID enclosure as storage

S

starkruzr

Renowned Member
Aug 28, 2014
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Washington, District of Columbia, United States
I'm using this USB3 (5Gbps, theoretically) RAID enclosure set to RAID10 as my storage for my VMs and I'm not sure but think my performance is worse than it was when I was using SATA drives connected in RAID0 to an LSI battery-backed, 512MB RAID card. How much worse should I expect? Is this going to be unusable? Should I configure it instead to use 3Gbps SATA II (eSATA) because of some performance burstiness with USB3 I'm not aware of?
 
I did some test some months ago with bonnie++ and a USB3 no name enclosure, and I found out the limiting factor to be the hard drive, ie I achieved 100MB/s of sequential write using bonnie++ wether it was over USB3 or SATA.

See this bonnie++ command output,

Consumer Harddrive over USB3 interface:

Version 1.97 ------Sequential Output------ --Sequential Input- --Random-

Concurrency 1 -Per Chr- --Block-- -Rewrite- -Per Chr- --Block-- --Seeks--

Machine Size K/sec %CP K/sec %CP K/sec %CP K/sec %CP K/sec %CP /sec %CP

django 31776M 897 99 102248 9 26867 3 4983 90 128649 6 166.2 2
Click to expand...


If you are conserned about storage performance could you please install bonnie++, run the command "bonnie++ " and post the results here for discussion.
This would give us hard numbers on which to base decisions.
 
Hm.

Code: 
root@cirrus:/media/usb0/images/100# bonnie++ -u root -d /media/usb0Using uid:0, gid:0.
Writing a byte at a time...done
Writing intelligently...done
Rewriting...done
Reading a byte at a time...done
Reading intelligently...done
start 'em...done...done...done...done...done...
Create files in sequential order...done.
Stat files in sequential order...done.
Delete files in sequential order...done.
Create files in random order...done.
Stat files in random order...done.
Delete files in random order...done.
Version  1.97       ------Sequential Output------ --Sequential Input- --Random-
Concurrency   1     -Per Chr- --Block-- -Rewrite- -Per Chr- --Block-- --Seeks--
Machine        Size K/sec %CP K/sec %CP K/sec %CP K/sec %CP K/sec %CP  /sec %CP
cirrus          63G  1142  99 198684   9 85828   6 +++++ +++ 196730  11 178.4   2
Latency              9457us     185ms    5482ms   13619us   46538us     205ms
Version  1.97       ------Sequential Create------ --------Random Create--------
cirrus              -Create-- --Read--- -Delete-- -Create-- --Read--- -Delete--
              files  /sec %CP  /sec %CP  /sec %CP  /sec %CP  /sec %CP  /sec %CP
                 16 +++++ +++ +++++ +++ +++++ +++ +++++ +++ +++++ +++ +++++ +++
Latency                36us     200us     223us      41us       8us      34us
1.97,1.97,cirrus,1,1436507958,63G,,1142,99,198684,9,85828,6,+++++,+++,196730,11,178.4,2,16,,,,,+++++,+++,+++++,+++,+++++,+++,+++++,+++,+++++,+++,+++++,+++,9457us,185ms,5482ms,13619us,46538us,205ms,36us,200us,223us,41us,8us,34us

What do you think?
 
200 MB/s is not that bad actually although I would personally stay away form Raid0, if you lose one disk you lose all your data !
Manu
 
starkruzr said:
What do you think?
Click to expand...
I think that:
1) you shouldn't use RAID0: too dangerous
2) you aren't giving a comparison, just USB-case figures
3) raw IO speed is not all: compare CPU load and latency too!

For 3, don't you think that it would be useless to have a storage that nearly halts your VMs when tranferring data?
 
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