Martchus
/
mdadm
1
0
Fork 0
Code Issues Pull Requests Projects Releases Wiki Activity

Documentation fixup for stripe_cache_size 

Signed-off-by: Dan Williams <dan.j.williams@intel.com>
This commit is contained in:
Dan Williams 2008-07-18 17:47:13 -07:00
parent a5ee6dfbf5
commit 800053d600
1 changed files with 9 additions and 6 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

15
md.4
View File

@ -526,19 +526,22 @@ Finally, "idle" can be written to stop the check/repair process.
.B md/stripe_cache_size
This is only available on RAID5 and RAID6. It records the size (in
pages per device) of the stripe cache which is used for synchronising
all read and write operations to the array. The default is 128.
all write operations to the array and all read operations if the array
is degraded. The default is 256. Valid values are 17 to 32768.
Increasing this number can increase performance in some situations, at
some cost in system memory.
some cost in system memory. Note, setting this value too high can
result in an "out of memory" condition for the system.
memory_consumed = system_page_size * nr_disks * stripe_cache_size
.TP
.B md/preread_bypass_threshold
This is only available on RAID5 and RAID6. This variable sets the
number of times MD will service a full-stripe-write before servicing a
stripe that requires some "prereading". For fairness this defaults to
1. Setting this to 0 maximizes sequential-write throughput at the cost
of fairness to threads doing small or random writes. Valid values are 0
to stripe_cache_size.
1. Valid values are 0 to stripe_cache_size. Setting this to 0
maximizes sequential-write throughput at the cost of fairness to threads
doing small or random writes.
.SS KERNEL PARAMETERS