in a device independent manner. Also include an example anticipatory
scheduler, gsched_rr, which gives very nice performance improvements
in presence of competing random access patterns.
This is joint work with Fabio Checconi, developed last year
and presented at BSDCan 2009. You can find details in the
README file or at
http://info.iet.unipi.it/~luigi/geom_sched/
to support various storage boxes which really aren't active-active.
We only write the label on the *first* provider. For all other providers
we just "add" the disk. This also allows for an "add" verb.
A usage implication is that you should specificy the currently active
storage path as the first provider.
Note that this does not add RDAC-like functionality, but better allows for
autovolumefailover configurations (additional checkins elsewhere will support
this).
Sponsored by: Panasas
MFC after: 1 month
Note that due to e.g. write throttling ('wdrain'), it can stall all the disk
I/O instead of just the device it's configured for. Using it for removable
media is therefore not a good idea.
Reviewed by: pjd (earlier version)
when trees were big and FAST mode was enabled by default.
So small block size doesn't benefits linear I/O operations in FAST and
significantly slowdowns in ECONOMIC (default) mode. For single stream random
I/Os so small block doesn't give much benefits, as access time is usually
bigger then transfer time there. Same time it requires all heads to seek
together for every single request, reducing performance on parallel load.
"split" is very ineffective for devices with rotating media as HDDs.
To be effective, it needs that transfer time reduction due to block
splitting was bigger then access time increase due to non-sequential
access. For modern HDDs I was able to reproduce it only with read sizes
of 2MB and above, which is almost not applicable in real life.
"load" algorithm same time is more universal and effective now.
Reviewed by: pjd
GEOM_PART does not exist in the kernel, and 2) the GEOM in
question does not exist.
Additionally abort in case of programming errors that result
in neither the class nor geom not being present in the gctl
request.
Submitted by: "Andrey V. Elsukov" <bu7cher@yandex.ru>
Approved by: re (kib)
gpart(8). LBAs in particular are ugly. The ganularity is a sector,
but users expect byte granularity when specifying the size or offset
with a SI unit. Handle LBAs specially to deal with this.
attributes. The start and end more accurately describe the
space taken by a partition. The offset and size are used to
describe the effective (usable) storage of that partition.
modify the pointer argument passed to it. This triggered an assert in malloc
when a geom command being run under the livefs environment.
PR: bin/130632
Submitted by: Dimitry Andric <dimitry -at- andric.com>
Pointy hat to: me
MFC after: 2 days
* Better wording of sections dealing with physical storage
* A new section on assumptions gvirstor has on its consumer devices
(components) and its interaction with file systems
* Improved markup (by hrs@)
Reviewed by: hrs
Approved by: gnn (mentor)
might do subsequent reads from other providers. This stopped geli (and
probably other classes using g_metadata_store as well) from being put on top
of gvinum raid5 volumes.
Note:
The reason it fails in the gvinum raid5 case is that gvinum will read back the
old parity stripe before calculating the new parity stripe to be written out
again. The write will then fail because the underlying disk to be read is
opened write only.
MFC after: 1 week
