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Diffstat (limited to 'share/man/man4/aac.4')
-rw-r--r-- | share/man/man4/aac.4 | 12 |
1 files changed, 12 insertions, 0 deletions
diff --git a/share/man/man4/aac.4 b/share/man/man4/aac.4 index 3988c4d..22167b9 100644 --- a/share/man/man4/aac.4 +++ b/share/man/man4/aac.4 @@ -100,6 +100,18 @@ disk/container interface .It Pa /boot/kernel/aac.ko aac loadable module .El +.Sh TUNING +The read-only sysctl +.Va hw.aac.iosize_max +defautls to 65536 and may be set at boot time to another value via +.Xr loader 8 . +This value determines the maximum data transfer size allowed +to/from an array. Setting it higher will result in better performance, +especially for large sequential access patterns. BEWARE: internal limitations +of the card limit this value to 64K for arrays with many members. While it +may be safe to raise this value, do so AT YOUR OWN RISK. Note also that +performance peaks at a value of 96K, and drops off dramatically at 128K, due +to other limitations of the card. .Sh DIAGNOSTICS Compiling with .Dv AAC_DEBUG |