[mythtv-users] Software RAID and ionice

[Richard Freeman]

Richard Freeman wrote:
> 
> In any case, I'll post some results with bonnie++.  I started to run
> tests and got IOBOUND on mythtv - despite running bonnie++ in the idle
> ionice class.  I'll run tests later today and post them...
> 

Ok, here is the output of bonnie++.  This was run as a normal user at 
without any (io)nicing of any kind:


Here are the stats for a regular ext3 partition directly on a 7200RPM 
ATA100 drive (no lvm2/raid/etc):

Version 1.93c       ------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
rich64           4G   312  94 11250   6  8301   3  1188  95 28460   4 
84.4   3
Latency             88477us   66596ms   64744ms   33653us     304ms 
1111ms
Version 1.93c       ------Sequential Create------ --------Random 
Create--------
rich64              -Create-- --Read--- -Delete-- -Create-- --Read--- 
-Delete--
               files  /sec %CP  /sec %CP  /sec %CP  /sec %CP  /sec %CP 
/sec %CP
                  16   976   2 +++++ +++ 21010  45 23846  57 +++++ +++ 
27417  59
Latency               140ms   45423us   61051us   10185us     138us 
20773us
1.93c,1.93c,rich64,1,1180012054,4G,,312,94,11250,6,8301,3,1188,95,28460,4,84.4,3,16,,,,,976,2,+++++,+++,21010,45,23846,57,+++++,+++,27417,59,88477us,66596ms,64744ms,33653us,304ms,1111ms,140ms,45423us,61051us,10185us,138us,20773us

And here is the data for the video partition running on top of lvm2 
running on top of raid5 on 3x 150MB/s SATA 7200RPM drives:

Version 1.93c       ------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
rich64           4G   254  87 12802   7  9057   6   992  89 45866  20 
180.5   7
Latency               379ms   38797ms     600ms   41686us     228ms 
415ms
Version 1.93c       ------Sequential Create------ --------Random 
Create--------
rich64              -Create-- --Read--- -Delete-- -Create-- --Read--- 
-Delete--
               files  /sec %CP  /sec %CP  /sec %CP  /sec %CP  /sec %CP 
/sec %CP
                  16  7809  20 +++++ +++ 16587  39  1408   3 +++++ +++ 
21378  49
Latency             77382us    3398us    6765us   13823us    8819us 
6155us

1.93c,1.93c,rich64,1,1180009338,4G,,254,87,12802,7,9057,6,992,89,45866,20,180.5,7,16,,,,,7809,20,+++++,+++,16587,39,1408,3,+++++,+++,21378,49,379ms,38797ms,600ms,41686us,228ms,415ms,77382us,3398us,6765us,13823us,8819us,6155us


The stats are fairly comparable - block writes are a hair slower, block 
reads are a lot faster - about what you'd expect.  In any case, the 
speed should be WAY more than needed to stream video at 1-2Mbps.