write. This way on first connection we will synchronize only the extents that
were modified during the lifetime of primary node, not entire GEOM provider.
MFC after: 3 days
reordering won't make the actual write to be committed before marking
the coresponding extent as dirty.
It can be disabled in configuration file.
If BIO_FLUSH is not supported by the underlying file system we log a warning
and never send BIO_FLUSH again to that GEOM provider.
MFC after: 3 days
disk if needed. This should fix a potential case when extents are cleared in
activemap but metadata is not updated on disk.
Suggested by: pjd
Approved by: pjd (mentor)
only receiving the data. In r220271 the unused directions were
disabled using shutdown(2).
Unfortunately, this broke automatic receive buffer sizing, which
currently works only for connections in ETASBLISHED state. It was a
root cause of the issue reported by users, when connection between
primary and secondary could get stuck.
Disable the code introduced in r220271 until the issue with automatic
buffer sizing is not resolved.
Reported by: Daniel Kalchev <daniel@digsys.bg>, danger, sobomax
Tested by: Daniel Kalchev <daniel@digsys.bg>, danger
Approved by: pjd (mentor)
MFC after: 1 week
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
secondary role. It is possible that the remote node is primary, but only
because there was a role change and it didn't finish cleaning up (unmounting
file systems, etc.). If we detect such situation, wait for the remote node
to switch the role to secondary before accepting I/Os. If we don't wait for
it in that case, we will most likely cause split-brain.
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
equal to secondary counters:
primary_localcnt = secondary_remotecnt
primary_remotecnt = secondary_localcnt
Previously it was done wrong and split-brain was observed after
primary had synchronized up-to-date data from secondary.
Approved by: pjd (mentor)
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
- HOLE - it simply turns all-zero blocks into few bytes header;
it is extremely fast, so it is turned on by default;
it is mostly intended to speed up initial synchronization
where we expect many zeros;
- LZF - very fast algorithm by Marc Alexander Lehmann, which shows
very decent compression ratio and has BSD license.
MFC after: 2 weeks
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
master process only and pass changes to the worker processes over control
socket. This removes access to global namespace in preparation for capsicum
sandboxing.
MFC after: 2 weeks
races - in this case a keepalive packet was send from wrong thread which
lead to connection dropping, because of corrupted packet.
Fix it by sending keepalive packets directly from the send thread.
As a bonus we now send keepalive packets only when connection is idle.
Submitted by: Mikolaj Golub <to.my.trociny@gmail.com>
MFC after: 3 days
