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
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
return a pointer to a void. The send_thread() and disk_thread()
funtions; however, do not have a return value because they run for
the duration of the daemon's lifetime. This causes gcc to barf when
running with -O3. Make these functions return a null pointer to quiet it.
PR: bin/124342
Submitted by: Garrett Cooper <gcooper@FreeBSD.org> (minus his comments)
MFC after: 1 week
the threading libraries is built. This simplifies the
logic in makefiles that need to check if the pthreads
support is present. It also fixes a bug where we would
build a threading library that we shouldn't have built:
for example, building with WITHOUT_LIBTHR and the default
value of DEFAULT_THREADING_LIB (libthr) would mistakenly
build the libthr library, but not install it.
Approved by: re (kensmith)
Change communication protocol to be much more resistant on network
problems and to allow for much better performance.
Better performance is achieved by creating two connections between
ggatec and ggated one for sending the data and one for receiving it.
Every connection is handled by separeted thread, so there is no more
synchronous data flow (send and wait for response), now one threads
sends all requests and another receives the data.
Use two threads in ggatec(8):
- sendtd, which takes I/O requests from the kernel and sends them to the
ggated daemon on the other end;
- recvtd, which waits for ggated responses and forwards them to the kernel.
Use three threads in ggated(8):
- recvtd, which waits for I/O requests and puts them onto incoming queue;
- disktd, which takes requests from the incoming queue, does disk operations
and puts finished requests onto outgoing queue;
- sendtd, which takes finished requests from the outgoing queue and sends
responses back to ggatec.
Because there were major changes in communication protocol, there is no
backward compatibility, from now on, both client and server has to run
on 5.x or 6.x (or at least ggated should be from the same FreeBSD version
on which ggatec is running).
For Gbit networks some buffers need to be increased. I use those settings:
kern.ipc.maxsockbuf=16777216
net.inet.tcp.sendspace=8388608
net.inet.tcp.recvspace=8388608
and I use '-S 4194304 -R 4194304' options for both, ggatec and ggated.
Approved by: re (scottl)
depending on namespace pollution in <sys/stat.h>. struct bintime is
only needed to satisfy leakage of kernel interfaces to userland and
namespace bugs in those interfaces...
This little thing can cause a deadlock, because taste mechanism start
to work after creation of ggate provider and I/O requests are sent from
other classes from the g_event thread, so number of pending events isn't 0.
Now ggatec(8) start second handshake and ggated(8) is trying to open
GEOM provider (for example md(4)) and it can't, because it hangs on
g_waitidle() in g_dev_open(). g_waitidle() cannot finish because
there is a pending read on event queue, and this read can't be
finished, because ggated(8) can't open target device.
GEOM Gate will recover from this deadlock, because requests will
timeout, but it of course isn't the best solution and I don't know
better one for now, so we should avoid opening GEOM providers while
there are pending requests in event queue.
