HAST allows to transparently store data on two physically separated machines
connected over the TCP/IP network. HAST works in Primary-Secondary
(Master-Backup, Master-Slave) configuration, which means that only one of the
cluster nodes can be active at any given time. Only Primary node is able to
handle I/O requests to HAST-managed devices. Currently HAST is limited to two
cluster nodes in total.
HAST operates on block level - it provides disk-like devices in /dev/hast/
directory for use by file systems and/or applications. Working on block level
makes it transparent for file systems and applications. There in no difference
between using HAST-provided device and raw disk, partition, etc. All of them
are just regular GEOM providers in FreeBSD.
For more information please consult hastd(8), hastctl(8) and hast.conf(5)
manual pages, as well as http://wiki.FreeBSD.org/HAST.
Sponsored by: FreeBSD Foundation
Sponsored by: OMCnet Internet Service GmbH
Sponsored by: TransIP BV
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)
zero stripeoffset in such case (as if device has no stripes), report offset
from the beginning of the media (as if device has single infinite stripe).
This gives partitioning tools information, required to guess better
partition alignment, in case if hardware doesn't report it's stripe size.
For example, it should give disklabel info about odd offset made by fdisk.
Fix some wrong usages.
Note: this does not affect generated binaries as this argument is not used.
PR: 137213
Submitted by: Eygene Ryabinkin (initial version)
MFC after: 1 month
- For SSDs use TRIM feature of DATA SET MANAGEMENT command, as defined by
ACS-2 specification working draft.
- For CompactFlash use CFA ERASE command, same as ad(4) does.
With this patch, `newfs -E /dev/ada1` was able to restore write speed of
my heavily weared OCZ Vertex SSD (firmware 1.4) up to the initial level
for the most part of it's capacity. Previous 1.3 firmware, even reportiong
TRIM capabilty bit set, was not working, reporting ABORT error for every
DSM command.
I have no idea whether it is normal, but for some reason it takes 200ms
to handle any TRIM command on this drive, that was making delete extremely
slow. But TRIM command is able to accept long list of LBAs and the length of
that list seems doesn't affect it's execution time. Implemented request
clusting algorithm allowed me to rise delete rate up to reasonable numbers,
when many parallel DELETE requests running.
- Instead of measuring last request execution time for each drive and
choosing one with smallest time, use averaged number of requests, running
on each drive. This information is more accurate and timely. It allows to
distribute load between drives in more even and predictable way.
- For each drive track offset of the last submitted request. If new request
offset matches previous one or close for some drive, prefer that drive.
It allows to significantly speedup simultaneous sequential reads.
PR: kern/113885
Reviewed by: sobomax
for specific "kinds" of disk labels - for example, GPT UUIDs. Reason
for this is that sometimes, other GEOM classes attach to these device
nodes instead of the proper ones - e.g. they attach to /dev/gptid/XXX
instead of /dev/ada0p2, which is annoying.
Reviewed by: pjd (earlier version)
MFC after: 1 month
This fixes a null pointer dereference with "gpart create -s GPT" after
the previous commit.
Reported by: Yuri Pankov
Pointyhat to: me
MFC after: 1 week
It is valid for an on-disk GPT header to report a header size which is
greater than 92 bytes. Previously, we would read in the sector and copy
only the 92 bytes that we know how to deal with before calculating the
checksum for comparison. This meant that when we did the checksum, we
overshot the buffer and took in random memory, so the checksum would fail.
We now determine the size of the header and allocate enough space to
preserve the entire on-disk contents. This allows us to be correctly
calculate the checksum and be able to modify and write the header back
to the disk, while preserving data that we might not understand.
Reported by: Kris Weston
Approved by: marcel@
MFC after: 2 weeks
depend on on-disk metadata. This was we won't attach to providers that are used
by other classes. For example we don't want to configure partitions on da0 if
it is part of gmirror, what we really want is partitions on mirror/foo.
During regular work it works like this: if provider is open for writing a class
receives the spoiled event from GEOM and detaches, once provider is closed the
taste event is send again and class can rediscover its metadata if it is still
there. This doesn't work that way when new class arrives, because GEOM gives
all existing providers for it to taste, also those open for writing. Classes
have to decided on their own if they want to deal with such providers (eg.
geom_dev) or not (classes modified by this commit).
Reported by: des, Oliver Lehmann <lehmann@ans-netz.de>
Tested by: des, Oliver Lehmann <lehmann@ans-netz.de>
Discussed with: phk, marcel
Reviewed by: marcel
MFC after: 3 days
code that merely emits an error and waits for a key press before
rebooting. The error being that extended partitions are not
bootable. The origin is presumed to be Windows 2000; Windows XP
does not do this...
For now, ignore the first 96 bytes when checking that the EBR is
(for the most part) all zeroes.
Tested by: Mario Lobo <mlobo@digiart.art.br>
MFC after: 1 week
It will be checked any way later by g_io_check() in g_io_schedule_down().
It is only needed here to not trigger panic from additional check, when
INVARIANTS enabled. So cover it with #ifdef INVARIANTS. It saves two
64bit divisions per request.
Remove msleep() timeout from g_io_schedule_up/down(). It works fine
without it, saving few percents of CPU on high request rates without
need to rearm callout twice per request.
