diff options
Diffstat (limited to 'sbin/vinum/vinum.8')
| -rw-r--r-- | sbin/vinum/vinum.8 | 8 |
1 files changed, 6 insertions, 2 deletions
diff --git a/sbin/vinum/vinum.8 b/sbin/vinum/vinum.8 index 87d008d..09e5714 100644 --- a/sbin/vinum/vinum.8 +++ b/sbin/vinum/vinum.8 @@ -2306,14 +2306,18 @@ performance. In particular, most systems use far too small a stripe size. The following discussion applies to all RAID systems, not just to .Nm vinum . .Pp -The FreeBSD block I/O system issues requests of between .5kB and 60 kB; a +The +.Fx +block I/O system issues requests of between .5kB and 60 kB; a typical mix is somewhere round 8 kB. You can't stop any striping system from breaking a request into two physical requests, and if you do it wrong it can be broken into several. This will result in a significant drop in performance: the decrease in transfer time per disk is offset by the order of magnitude greater increase in latency. .Pp -With modern disk sizes and the FreeBSD I/O system, you can expect to have a +With modern disk sizes and the +.Fx +I/O system, you can expect to have a reasonably small number of fragmented requests with a stripe size between 256 kB and 512 kB; with correct RAID implementations there is no obvious reason not to increase the size to 2 or 4 MB on a large disk. |
