o Detect when Boot Camp is enabled (i.e. the MBR mirrors the GPT).
o When Boot Camp is enabled, update the MBR whenever we write the GPT.
o Creation of a Boot Camp enabled GPT is not supported.
o Automatically disable Boot Camp when the GPT has been changed so that
there's either no EFI partition or no HFS+ partition.
o The first 4 partitions (by index) get mirrored in the MBR.
Requested by, discussed with and tested by: kris@pcbsd.org
MFC after: 1 week
filesystems to be opened for writing. This functionality used to
be special-cased for just the root filesystem, but with this change
is now available for all UFS filesystems. This change is needed for
journaled soft updates recovery.
Discussed with: Jeff Roberson
This fixes the problem, when the secondary GPT header is not erased when
partition table destroyed. Move equal operations from g_part_gpt_create
and g_part_gpt_recover to the separate function g_gpt_set_defaults.
Reported by: dwhite
MFC after: 1 week
Remove message about non empty bootcode, we can not break something
while GEOM_PART_EBR_COMPAT is defined.
But without GEOM_PART_EBR_COMPAT any changes in EBR are allowed and we
can accidentally wipe the boot code. To do not break anything save
the first EBR chunk and keep it untouched each time when we are
changing EBR. Note that we are still not support boot code for EBR.
PR: kern/141235
MFC after: 1 month
disk drive. The boot0cfg(8) utility preserves these 4 bytes when is
writing bootcode to keep a multiboot ability.
Change gpart's bootcode method to keep DSN if it is not zero. Also
do not allow writing bootcode with size not equal to MBRSIZE.
PR: kern/157819
Tested by: Eir Nym
MFC after: 1 month
Since the only parameter that we check is size of bootcode, then
allow only two sizes: size of boot1 and size of /boot/boot.
This partially protects users from losing ability to boot if incorrect
bootcode is specified.
Requested by: ru
DEVFS, and make it accessible via the diskinfo utility.
Extend GEOM's generic attribute query mechanism into generic disk consumers.
sys/geom/geom_disk.c:
sys/geom/geom_disk.h:
sys/cam/scsi/scsi_da.c:
sys/cam/ata/ata_da.c:
- Allow disk providers to implement a new method which can override
the default BIO_GETATTR response, d_getattr(struct bio *). This
function returns -1 if not handled, otherwise it returns 0 or an
errno to be passed to g_io_deliver().
sys/cam/scsi/scsi_da.c:
sys/cam/ata/ata_da.c:
- Don't copy the serial number to dp->d_ident anymore, as the CAM XPT
is now responsible for returning this information via
d_getattr()->(a)dagetattr()->xpt_getatr().
sys/geom/geom_dev.c:
- Implement a new ioctl, DIOCGPHYSPATH, which returns the GEOM
attribute "GEOM::physpath", if possible. If the attribute request
returns a zero-length string, ENOENT is returned.
usr.sbin/diskinfo/diskinfo.c:
- If the DIOCGPHYSPATH ioctl is successful, report physical path
data when diskinfo is executed with the '-v' option.
Submitted by: will
Reviewed by: gibbs
Sponsored by: Spectra Logic Corporation
Add generic attribute change notification support to GEOM.
sys/sys/geom/geom.h:
Add a new attrchanged method field to both g_class
and g_geom.
sys/sys/geom/geom.h:
sys/geom/geom_event.c:
- Provide the g_attr_changed() function that providers
can use to advertise attribute changes.
- Perform delivery of attribute change notifications
from a thread context via the standard GEOM event
mechanism.
sys/geom/geom_subr.c:
Inherit the attrchanged method from class to geom (class instance).
sys/geom/geom_disk.c:
Provide disk_attr_changed() to provide g_attr_changed() access
to consumers of the disk API.
sys/cam/scsi/scsi_pass.c:
sys/cam/scsi/scsi_da.c:
sys/geom/geom_dev.c:
sys/geom/geom_disk.c:
Use attribute changed events to track updates to physical path
information.
sys/cam/scsi/scsi_da.c:
Add AC_ADVINFO_CHANGED to the registered asynchronous CAM
events for this driver. When this event occurs, and
the updated buffer type references our physical path
attribute, emit a GEOM attribute changed event via the
disk_attr_changed() API.
sys/cam/scsi/scsi_pass.c:
Add AC_ADVINFO_CHANGED to the registered asynchronous CAM
events for this driver. When this event occurs, update
the physical patch devfs alias for this pass instance.
Submitted by: gibbs
Sponsored by: Spectra Logic Corporation
They are media-dependent and may change in run-time, same as sectorsize
and/or mediasize.
SCSI devices return physical sector size and offset via READ CAPACITY(16)
command and so can not report it until media inserted or at least until
probe sequence completed. UNMAP support is also reported there.
geometry and partitions may start from withing the first track.
If we found such partitions, then do not reserve space of the
first track, only first sector.
partition tables and lost an ability to boot after r221788.
Also unhide an error message from bootverbose, this would help to
easier determine the problem.
probed and read successfull, but it contains invalid values (e.g.
overlapped partitions, offset or size is out of bounds), then table
will be rejected.
MFC after: 1 month
was not updated to pass CRD_F_KEY_EXPLICIT flag to opencrypto. This resulted in
always using first key.
We need to support providers created with this bug, so set special
G_ELI_FLAG_FIRST_KEY flag for GELI provider in integrity mode with version
smaller than 6 and pass the CRD_F_KEY_EXPLICIT flag to opencrypto only if
G_ELI_FLAG_FIRST_KEY doesn't exist.
Reported by: Anton Yuzhaninov <citrin@citrin.ru>
MFC after: 1 week
cpuset_t objects.
That is going to offer the underlying support for a simple bump of
MAXCPU and then support for number of cpus > 32 (as it is today).
Right now, cpumask_t is an int, 32 bits on all our supported architecture.
cpumask_t on the other side is implemented as an array of longs, and
easilly extendible by definition.
The architectures touched by this commit are the following:
- amd64
- i386
- pc98
- arm
- ia64
- XEN
while the others are still missing.
Userland is believed to be fully converted with the changes contained
here.
Some technical notes:
- This commit may be considered an ABI nop for all the architectures
different from amd64 and ia64 (and sparc64 in the future)
- per-cpu members, which are now converted to cpuset_t, needs to be
accessed avoiding migration, because the size of cpuset_t should be
considered unknown
- size of cpuset_t objects is different from kernel and userland (this is
primirally done in order to leave some more space in userland to cope
with KBI extensions). If you need to access kernel cpuset_t from the
userland please refer to example in this patch on how to do that
correctly (kgdb may be a good source, for example).
- Support for other architectures is going to be added soon
- Only MAXCPU for amd64 is bumped now
The patch has been tested by sbruno and Nicholas Esborn on opteron
4 x 12 pack CPUs. More testing on big SMP is expected to came soon.
pluknet tested the patch with his 8-ways on both amd64 and i386.
Tested by: pluknet, sbruno, gianni, Nicholas Esborn
Reviewed by: jeff, jhb, sbruno
device in /dev/ create symbolic link with adY name, trying to mimic old ATA
numbering. Imitation is not complete, but should be enough in most cases to
mount file systems without touching /etc/fstab.
- To know what behavior to mimic, restore ATA_STATIC_ID option in cases
where it was present before.
- Add some more details to UPDATING.
bytes. Remove bogus assertion and while here remove another too obvious
assertion.
Reported by: Fabian Keil <freebsd-listen@fabiankeil.de>
MFC after: 2 weeks
allocate all of them at attach time. This allows to avoid moving
keys around in the most-recently-used queue and needs no mutex
synchronization nor refcounting.
MFC after: 2 weeks
create reasonably large cache for the keys that is filled when
needed. The previous version was problematic for very large providers
(hundreds of terabytes or serval petabytes). Every terabyte of data
needs around 256kB for keys. Make the default cache limit big enough
to fit all the keys needed for 4TB providers, which will eat at most
1MB of memory.
MFC after: 2 weeks
embedded flash stores.
Some devices - notably those with uboot - don't have an
explicit partition table (eg like Redboot's FIS.)
geom_map thus provides an easy way to export the hard-coded
flash layout as geom providers for use by filesystems and
other tools.
It also includes a "search" function which allows for
dynamic creation of partition layouts where the device only
has a single hard-coded partition. For example, if
there is a "kernel+rootfs" partition, a single image can
be created which appends the rootfs after the kernel with
an appropriate search string. geom_map can be told to
search for said search string and create a partition
beginning after it.
Submitted by: Aleksandr Rybalko <ray@dlink.ua>
bio_children > 1, g_destroy_bio() is never called and the bio
leaks. Fix this by calling g_destroy_bio() earlier, before the check.
Submitted by: Victor Balada Diaz <victor@bsdes.net> (initial version)
Approved by: pjd (mentor)
MFC after: 1 week
g_io_deliver(). In such case it increases 'pace' counter on each ENOMEM and
reschedules the request. The 'pace' counter is decreased for each request going
down, but until 'pace' is greater than zero, GEOM will handle at most 10
requests per second. For GEOM GATE users that are proxy to local GEOM providers
(like ggatel(8) and HAST) we can end up with almost permanent slow down of GEOM
down queue. This is because once we reach GEOM GATE queue limit, we return
ENOMEM to the GEOM. This means that we have, eg. 1024 I/O requests in the GEOM
GATE queue. To make room in the queue and stop returning ENOMEM we need to
proceed the requests of course, but those requests are handled by userland
daemons that handle them by reading/writing also from/to local GEOM providers.
For example with HAST, a new requests comes to /dev/hast/data, which is GEOM
GATE provider. GEOM GATE passes the request to hastd(8) and hastd(8)
reads/writes from/to /dev/da0. Once we reach GEOM GATE queue limit, to free up
a slot in GEOM GATE queue, hastd(8) has to read/write from/to /dev/da0, but
this request will also be very slow, because GEOM now slows down all the
requests. We end up with full queue that we can unload at the speed of 10
requests per second. This simply looks like a deadlock.
Fix it by allowing userland daemons that work with both GEOM GATE and local
GEOM providers to specify unlimited queue size, so GEOM GATE will never return
ENOMEM to the GEOM.
MFC after: 1 week
registered in g_gate_units array and when its sc_provider field is
filled. If during this period g_gate_units is accessed by another
thread that is checking for provider name collision the crash is
possible.
Fix this by adding sc_name field to struct g_gate_softc. In
g_gate_create() when g_gate_softc is created but sc_provider is still
not sc_name points to provider name stored in the local array.
Approved by: pjd (mentor)
Reported by: Freddie Cash <fjwcash@gmail.com>
MFC after: 1 week
Add new RAID GEOM class, that is going to replace ataraid(4) in supporting
various BIOS-based software RAIDs. Unlike ataraid(4) this implementation
does not depend on legacy ata(4) subsystem and can be used with any disk
drivers, including new CAM-based ones (ahci(4), siis(4), mvs(4), ata(4)
with `options ATA_CAM`). To make code more readable and extensible, this
implementation follows modular design, including core part and two sets
of modules, implementing support for different metadata formats and RAID
levels.
Support for such popular metadata formats is now implemented:
Intel, JMicron, NVIDIA, Promise (also used by AMD/ATI) and SiliconImage.
Such RAID levels are now supported:
RAID0, RAID1, RAID1E, RAID10, SINGLE, CONCAT.
For any all of these RAID levels and metadata formats this class supports
full cycle of volume operations: reading, writing, creation, deletion,
disk removal and insertion, rebuilding, dirty shutdown detection
and resynchronization, bad sector recovery, faulty disks tracking,
hot-spare disks. For Intel and Promise formats there is support multiple
volumes per disk set.
Look graid(8) manual page for additional details.
Co-authored by: imp
Sponsored by: Cisco Systems, Inc. and iXsystems, Inc.
Introduce new type of BIO_GETATTR -- GEOM::setstate, used to inform lower
GEOM about state of it's providers from the point of upper layers.
Make geom_disk use led(4) subsystem to illuminate states in such fashion:
FAILED - "1" (on), REBUILD - "f5" (slow blink), RESYNC - "f1" (fast blink),
ACTIVE - "0" (off).
LED name should be set for each disk via kern.geom.disk.%s.led sysctl.
Later disk API could be extended to allow disk driver to report this info
in custom way via it's own facilities.
Change BIO_GETATTR("GEOM::kerneldump") API to make set_dumper() called by
consumer (geom_dev) instead of provider (geom_disk). This allows any geom
insert it's code into the dump call chain, implementing more sophisticated
functionality then just disk partitioning.
'/boot', which confuses the devfs code and can cause userland programs to
fail reading /dev/ext2fs directory with weird error code, such as any
program that uses pwlib.
Strip any leading slashes before feeding the label to the geom_label code.
Sponsored by: Sippy Software, Inc.
MFC after: 1 week
No FreeBSD version bump, the userland application to query the features will
be committed last and can serve as an indication of the availablility if
needed.
Sponsored by: Google Summer of Code 2010
Submitted by: kibab
Reviewed by: silence on geom@ during 2 weeks
X-MFC after: to be determined in last commit with code from this project
The algorithm is supposed to work as follows:
in order to prevent starvation, when a new client starts being served we
record the start time and reset the counter of bytes served.
We then switch to a new client after a certain amount of time or bytes,
even if the current one still has pending requests.
To avoid charging a new client the time of the first seek,
we start counting time when the first request is served.
Unfortunately a bug in the previous version of the code failed
to set the start time in certain cases, resulting in some processes
exceeding their timeslice.
The fix (in this patch) is trivial, though it took a while to find
out and replicate the bug.
Thanks to Tommaso Caprai for investigating and fixing the problem.
Submitted by: Tommaso Caprai
MFC after: 1 week
EBR schemes: fat32, ebr, linux-data, linux-raid, linux-swap and
linux-lvm. Add bios-boot GUID and alias for the GPT scheme. It used by
GRUB 2 loader. Also do sorting definitions of types in diskmbr.h
and in g_part.c.
PR: bin/120990, kern/147664
MFC after: 2 weeks
unfunctional. Wiring the user buffer has only been done explicitly
since r101422.
Mark the kern.disks sysctl as MPSAFE since it is and it seems to have
been mis-using the NOLOCK flag.
Partially break the KPI (but not the KBI) for the sysctl_req 'lock'
field since this member should be private and the "REQ_LOCKED" state
seems meaningless now.
and can prevent kernel memory exhausting when big value is specified
from command line.
Split reading and writing operation to several iteration to do not
trigger KASSERT when data length is greater than MAXPHYS.
PR: kern/144962, kern/147851
MFC after: 2 weeks
was specified incorrectly, causing the bzero to run past the end of a
malloc(9)'d object.
Submitted by: Eric Youngblut < eyoungblut AT isilon DOT com >
MFC after: 3 days
small non fatal inconsistency. EBR may contain boot loader and sometimes
it just has some garbage data. Now this does not prevent FreeBSD to use
extended partitions. But since we do not support bootcode for EBR we mark
tables which have non empty boot area as corrupt. This does make them
readonly and we can not damage this data.
PR: kern/141235
MFC after: 1 month
and replace tsleep(9) with msleep(9) which doesn't use a timeout. The
previously used timeout caused the event process to wake up ten times
per second on an idle system.
one_event() is now called with the topology lock held and it returns
with both the topology and event locks held when there are no more
events in the queue.
Reported by: mav, Marius Nünnerich
Reviewed by: freebsd-geom
during boot.
Change the last argument of gets() to indicate a visibility flag and add
definitions for the numerical constants. Except for the value 2, gets()
will behave exactly the same, so existing consumers shouldn't break. We
only use it in two places, though.
Submitted by: lme (older version)
"arg0 'provider': Invalid argument" after creating new partition
table.
Move code for search of existing geom into g_part_find_geom
function and use this function instead of g_part_parm_geom
in g_part_ctl_create.
Approved by: kib (mentor)
of the EV_DONE flag and use the mutex to protect against losing wakeups
in g_waitfor_event().
Reported by: davidxu
Tested by: davidxu
Discussed on: freebsd-current
This was needed for recover implementation.
Implement the recover command for GPT. Now GPT will marked as
corrupt when any of three types of corruption will be detected:
1. Damaged primary GPT header or table
2. Damaged secondary GPT header or table
3. Secondary header is not located in the last LBA
Marked GPT becomes read-only. Any changes with corrupt table
are prohibited. Only "destroy" and "recover" commands are allowed.
Discussed with: geom@ (mostly silence)
Tested by: Ilya A. Arhipov
Approved by: mav (mentor)
MFC after: 2 weeks
information that device is already suspended or that device is using
one-time key and suspend is not supported.
- 'geli suspend -a' silently skips devices that use one-time key, this is fine,
but because we log which device were suspended on the console, log also which
devices were skipped.
Before this change if you wanted to suspend your laptop and be sure that your
encryption keys are safe, you had to stop all processes that use file system
stored on encrypted device, unmount the file system and detach geli provider.
This isn't very handy. If you are a lucky user of a laptop where suspend/resume
actually works with FreeBSD (I'm not!) you most likely want to suspend your
laptop, because you don't want to start everything over again when you turn
your laptop back on.
And this is where geli suspend/resume steps in. When you execute:
# geli suspend -a
geli will wait for all in-flight I/O requests, suspend new I/O requests, remove
all geli sensitive data from the kernel memory (like encryption keys) and will
wait for either 'geli resume' or 'geli detach'.
Now with no keys in memory you can suspend your laptop without stopping any
processes or unmounting any file systems.
When you resume your laptop you have to resume geli devices using 'geli resume'
command. You need to provide your passphrase, etc. again so the keys can be
restored and suspended I/O requests released.
Of course you need to remember that 'geli suspend' won't clear file system
cache and other places where data from your geli-encrypted file system might be
present. But to get rid of those stopping processes and unmounting file system
won't help either - you have to turn your laptop off. Be warned.
Also note, that suspending geli device which contains file system with geli
utility (or anything used by 'geli resume') is not very good idea, as you won't
be able to resume it - when you execute geli(8), the kernel will try to read it
and this read I/O request will be suspended.
and print a diagnostic if the call fails.
This avoids a panic when a device with an invalid name is attempted to
be registered. For example the label class gets device names from
untrusted input.
Reviewed by: freebsd-geom
attribute (it should be allowed only to unset it), but for test purposes it
might be useful, so the current code allows it.
Reviewed by: arch@ (Message-ID: <20100917234542.GE1902@garage.freebsd.pl>)
MFC after: 2 weeks
confusing.
Note there is still no information about 'partcode' being written to disk
(gpart bootcode -p <partcode> <disk>).
Maybe in the future all the messages printed by gpart(8) on success could be
hidden under -v?
PR: bin/150239
Reported by: Roddi <roddi@me.com>
Submitted by: arundel
MFC after: 2 weeks
understand everything correctly, we don't really need it.
- Provide default numeric value as strings. This allows to simplify
a lot of code.
- Bump version number.
Add the BIO_ORDERED flag for struct bio and update bio clients to use it.
The barrier semantics of bioq_insert_tail() were broken in two ways:
o In bioq_disksort(), an added bio could be inserted at the head of
the queue, even when a barrier was present, if the sort key for
the new entry was less than that of the last queued barrier bio.
o The last_offset used to generate the sort key for newly queued bios
did not stay at the position of the barrier until either the
barrier was de-queued, or a new barrier (which updates last_offset)
was queued. When a barrier is in effect, we know that the disk
will pass through the barrier position just before the
"blocked bios" are released, so using the barrier's offset for
last_offset is the optimal choice.
sys/geom/sched/subr_disk.c:
sys/kern/subr_disk.c:
o Update last_offset in bioq_insert_tail().
o Only update last_offset in bioq_remove() if the removed bio is
at the head of the queue (typically due to a call via
bioq_takefirst()) and no barrier is active.
o In bioq_disksort(), if we have a barrier (insert_point is non-NULL),
set prev to the barrier and cur to it's next element. Now that
last_offset is kept at the barrier position, this change isn't
strictly necessary, but since we have to take a decision branch
anyway, it does avoid one, no-op, loop iteration in the while
loop that immediately follows.
o In bioq_disksort(), bypass the normal sort for bios with the
BIO_ORDERED attribute and instead insert them into the queue
with bioq_insert_tail(). bioq_insert_tail() not only gives
the desired command order during insertion, but also provides
barrier semantics so that commands disksorted in the future
cannot pass the just enqueued transaction.
sys/sys/bio.h:
Add BIO_ORDERED as bit 4 of the bio_flags field in struct bio.
sys/cam/ata/ata_da.c:
sys/cam/scsi/scsi_da.c
Use an ordered command for SCSI/ATA-NCQ commands issued in
response to bios with the BIO_ORDERED flag set.
sys/cam/scsi/scsi_da.c
Use an ordered tag when issuing a synchronize cache command.
Wrap some lines to 80 columns.
sys/cddl/contrib/opensolaris/uts/common/fs/zfs/vdev_geom.c
sys/geom/geom_io.c
Mark bios with the BIO_FLUSH command as BIO_ORDERED.
Sponsored by: Spectra Logic Corporation
MFC after: 1 month
but because of a bug it was a no-op, so we were still using offsets in native
byte order for the host. Do it properly this time, bump version to 4 and set
the G_ELI_FLAG_NATIVE_BYTE_ORDER flag when version is under 4.
MFC after: 2 weeks
via %s
Most of the cases looked harmless, but this is done for the sake of
correctness. In one case it even allowed to drop an intermediate buffer.
Found by: clang
MFC after: 2 week
deadlock fixed in r207671.
- Wait for worker process to exit at class unload. The worker process
was not guaranteed to exit before the linker unloaded the module.
- Use 0 as the worker process exit status instead of ENXIO and style
the NOTREACHED comment.
Reviewed by: lulf
X-MFC after: r207671
proceed while g_unload_class() blocks the event thread. Fix this by not
running g_unload_class() as a GEOM event and dropping the topology lock
when withering needs to proceed.
PR: kern/139847
Silence on: freebsd-geom
do not constitute user-visible or active partitions and as such should
not prevent undoing pending operations.
While here, initialize the last usable sector for the placeholder geom
based on the null scheme, created to allow undoing the destruction of
a scheme. This gives consistent output with "gpart show".
Based on a patch from: "Andrey V. Elsukov" <bu7cher@yandex.ru>
Previsouly this condition was reported with EIO by bio_offset > mediasize
check.
Perhaps that check should be extended to bio_offset+bio_length > mediasize.
MFC after: 1 week
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/
In other words, deny multiple read-only mounts of the same device.
Shared read-only mounts should theoretically be possible, but,
unfortunately, can not be implemented correctly using current
buffer cache code/interface and results in an eventual system crash.
Also, using nullfs seems to be a more efficient way to achieve the same
goal.
This gets us back to where we were before GEOM and where other BSDs are.
Submitted by: pjd (idea for checking for shared mounting)
Discussed with: phk, pjd
Silence from: fs@, geom@
MFC after: 2 weeks
In r205860 I missed the fact that there is code that strongly assumes
that devvp bo_bsize is equal to underlying provider's sectorsize.
In those places it is hard to obtain the sectorsize in an alternative
way if devvp bo_bsize is set to something else.
So, I am reverting bo_bsize assigment in g_vfs_open.
Instead, in getblk I use DEV_BSIZE block size for b_offset calculation
if vp is a disk vp as reported by vn_isdisk. This should coinside with
vp being a devvp.
Reported by: Mykola Dzham <i@levsha.me>
Tested by: Mykola Dzham <i@levsha.me>
Pointyhat to: avg
MFC after: 2 weeks
X-ToDo: convert bread(devvp) in all fs to use bo_bsize-d blocks
Because of how breadn -> bufstrategy -> g_vfs_strategy are currently
implemented, bread on devvp always expects DEV_BSIZE block size.
Thus, devvp bo_bsize must always be DEV_BSIZE irrespective of media
properties or filesystem implementation details.
Reviewed by: mckusick
MFC after: 2 weeks
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
provider names.
- Characters in range 0x01-0x1f except '\t', '\n', and '\r' are replaced
with '?'. Those characters are disallowed in XML.
- '&', '<', '>', '\'', '"' and characters in range 0x7f-0xff are
replaced with XML numeric character reference.
If the kern.geom.confxml sysctl provides invalid XML, libgeom
geom_xml2tree() fails and utilities using it do not work. Unsafe
characters are common in msdosfs and cd9660 labels.
PR: kern/104389
Submitted by: Doug Steinwand (original version)
Reviewed by: pjd
Discussed on: freebsd-geom
MFC after: 3 weeks
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
