requests as well as number of activemap updates.
Number of BIO_WRITEs and activemap updates are especially interesting, because
if those two are too close to each other, it means that your workload needs
bigger number of dirty extents. Activemap should be updated as rarely as
possible.
MFC after: 1 week
because we need to do ioctl(2)s, which are not permitted in the capability
mode. What we do now is to chroot(2) to /var/empty, which restricts access
to file system name space and we drop privileges to hast user and hast
group.
This still allows to access to other name spaces, like list of processes,
network and sysvipc.
To address that, use jail(2) instead of chroot(2). Using jail(2) will restrict
access to process table, network (we use ip-less jails) and sysvipc (if
security.jail.sysvipc_allowed is turned off). This provides much better
separation.
MFC after: 1 week
- We have two nodes connected and synchronized (local counters on both sides
are 0).
- We take secondary down and recreate it.
- Primary connects to it and starts synchronization (but local counters are
still 0).
- We switch the roles.
- Synchronization restarts but data is synchronized now from new primary
(because local counters are 0) that doesn't have new data yet.
This fix this issue we bump local counter on primary when we discover that
connected secondary was recreated and has no data yet.
Reported by: trociny
Discussed with: trociny
Tested by: trociny
MFC after: 1 week
Before it could change later and we were sending invalid mapsize.
Some time ago I added optimization where when nodes are connected for the
first time and there were no writes to them yet, there is no initial full
synchronization. This bug prevented it from working.
MFC after: 1 week
We can use capsicum for secondary worker processes and hastctl.
When working as primary we drop privileges using chroot+setgid+setuid
still as we need to send ioctl(2)s to ggate device, for which capsicum
doesn't allow (yet).
X-MFC after: capsicum is merged to stable/8
This way we know how to connect to secondary node when we are primary.
The same variable is used by the secondary node - it only accepts
connections from the address stored in 'remote' variable.
In cluster configurations it is common that each node has its individual
IP address and there is one addtional shared IP address which is assigned
to primary node. It seems it is possible that if the shared IP address is
from the same network as the individual IP address it might be choosen by
the kernel as a source address for connection with the secondary node.
Such connection will be rejected by secondary, as it doesn't come from
primary node individual IP.
Add 'source' variable that allows to specify source IP address we want to
bind to before connecting to the secondary node.
MFC after: 1 week
connection so the worker will exit if it does not receive packets from
the primary during this interval.
Reported by: Christian Vogt <Christian.Vogt@haw-hamburg.de>
Tested by: Christian Vogt <Christian.Vogt@haw-hamburg.de>
Approved by: pjd (mentor)
MFC after: 1 week
worker can ask the main privileged process to connect in worker's behalf
and then we can migrate descriptor using this socketpair to worker.
This is not really needed now, but will be needed once we start to use
capsicum for sandboxing.
MFC after: 1 week
to syslog if we run in background.
- Asserts in proto.c that method we want to call is implemented and remove
dummy methods from protocols implementation that are only there to abort
the program with nice message.
MFC after: 1 week
Accepting connections and handshaking in secondary is still done before
dropping privileges. It should be implemented by only accepting connections in
privileged main process and passing connection descriptors to the worker, but
is not implemented yet.
MFC after: 1 week
initialize all the data. This is huge waste of time and resources if
there were no writes yet, as there is no real data to synchronize.
Optimize this by sending "virgin" argument to secondary, which gives it a hint
that synchronization is not needed.
In the common case (where noth nodes are configured at the same time) instead
of synchronizing everything, we don't synchronize at all.
MFC after: 1 week
This way the primary process inherits signal mask from the main process,
which fixes a race where signal is delivered to the primary process before
configuring signal mask.
Reported by: Mikolaj Golub <to.my.trociny@gmail.com>
MFC after: 3 days
while the main process sends control message to the worker process, but worker
process hasn't started control thread yet, because it waits for reply from the
main process.
The fix is to start the control thread before sending any events.
Reported and fix suggested by: Mikolaj Golub <to.my.trociny@gmail.com>
MFC after: 3 days
limited to async-signal safe functions in the child process), move all hooks
execution to the main (non-threaded) process.
Do it by maintaining connection (socketpair) between child and parent
and sending events from the child to parent, so it can execute the hook.
This is step in right direction for others reasons too. For example there is
one less problem to drop privs in worker processes.
MFC after: 2 weeks
Obtained from: Wheel Systems Sp. z o.o. http://www.wheelsystems.com
node failures quickly for HAST resources that are rarely modified.
Remove XXX from a comment now that the guard thread never sleeps infinitely.
MFC after: 2 weeks
Obtained from: Wheel Systems Sp. z o.o. http://www.wheelsystems.com
secondary, which died between send(2) and recv(2). Do it by adding timeout
to recv(2) for primary incoming and outgoing sockets and secondary outgoing
socket.
Reported by: Mikolaj Golub <to.my.trociny@gmail.com>
Tested by: Mikolaj Golub <to.my.trociny@gmail.com>
MFC after: 3 days
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
