We can avoid spurious data divergence caused by partially-ignored
discards on certain backends with discard_zeroes_data=0, if we
translate partial unaligned discard requests into explicit zero-out.
The relevant use case is LVM/DM thin.
If on different nodes, DRBD is backed by devices with differing
discard characteristics, discards may lead to data divergence
(old data or garbage left over on one backend, zeroes due to
unmapped areas on the other backend). Online verify would now
potentially report tons of spurious differences.
While probably harmless for most use cases (fstrim on a file system),
DRBD cannot have that, it would violate our promise to upper layers
that our data instances on the nodes are identical.
To be correct and play safe (make sure data is identical on both copies),
we would have to disable discard support, if our local backend (on a
Primary) does not support "discard_zeroes_data=true".
We'd also have to translate discards to explicit zero-out on the
receiving (typically: Secondary) side, unless the receiving side
supports "discard_zeroes_data=true".
Which both would allocate those blocks, instead of unmapping them,
in contrast with expectations.
LVM/DM thin does set discard_zeroes_data=0,
because it silently ignores discards to partial chunks.
We can work around this by checking the alignment first.
For unaligned (wrt. alignment and granularity) or too small discards,
we zero-out the initial (and/or) trailing unaligned partial chunks,
but discard all the aligned full chunks.
At least for LVM/DM thin, the result is effectively "discard_zeroes_data=1".
Arguably it should behave this way internally, by default,
and we'll try to make that happen.
But our workaround is still valid for already deployed setups,
and for other devices that may behave this way.
Setting discard-zeroes-if-aligned=yes will allow DRBD to use
discards, and to announce discard_zeroes_data=true, even on
backends that announce discard_zeroes_data=false.
Setting discard-zeroes-if-aligned=no will cause DRBD to always
fall-back to zero-out on the receiving side, and to not even
announce discard capabilities on the Primary, if the respective
backend announces discard_zeroes_data=false.
We used to ignore the discard_zeroes_data setting completely.
To not break established and expected behaviour, and suddenly
cause fstrim on thin-provisioned LVs to run out-of-space,
instead of freeing up space, the default value is "yes".
Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
As long as the value is 0 the feature is disabled. With setting
it to a positive value, DRBD limits and aligns its resync requests
to the rs-discard-granularity setting. If the sync source detects
all zeros in such a block, the resync target discards the range
on disk.
Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
The status command originates the drbd9 code base. While for now we
keep the status information in /proc/drbd available, this commit
allows the user base to gracefully migrate their monitoring
infrastructure to the new status reporting interface.
In drbd9 no status information is exposed through /proc/drbd.
Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
The events2 command originates from drbd-9 development. It features
more information but requires a incompatible change in output
format.
Therefore the previous events command continues to exist, the new
improved events2 command becomes available now.
This prepares the user-base for a later switch to the complete
drbd9 code base.
Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
In setups involving a DRBD-proxy and connections that experience a lot of
buffer-bloat it might be necessary to set ping-timeout to an
unusual high value. By default DRBD uses the same value to wait if a newly
established TCP-connection is stable. Since the DRBD-proxy is usually located
in the same data center such a long wait time may hinder DRBD's connect process.
In such setups socket-check-timeout should be set to
at least to the round trip time between DRBD and DRBD-proxy. I.e. in most
cases to 1.
Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
Checksum based resync trades CPU cycles for network bandwidth,
in situations where we expect much of the to-be-resynced blocks
to be actually identical on both sides already.
In a "network hickup" scenario, it won't help:
all to-be-resynced blocks will typically be different.
The use case is for the resync of *potentially* different blocks
after crash recovery -- the crash recovery had marked larger areas
(those covered by the activity log) as need-to-be-resynced,
just in case. Most of those blocks will be identical.
This option makes it possible to configure checksum based resync,
but only actually use it for the first resync after primary crash.
Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
Allow to change the AL layout with an resize operation. For that
the reisze command gets two new fields: al_stripes and al_stripe_size.
In order to make the operation crash save:
1) Lock out all IO and MD-IO
2) Write the super block with MDF_PRIMARY_IND clear
3) write the bitmap to the new location (all zeros, since
we allow only while connected)
4) Initialize the new AL-area
5) Write the super block with the restored MDF_PRIMARY_IND.
6) Unfreeze all IO
Since the AL-layout has no influence on the protocol, this operation
needs to be beforemed on both sides of a resource (if intended).
Signed-off-by: Andreas Gruenbacher <agruen@linbit.com>
Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
We now can schedule only a specific range of sectors for online verify,
or interrupt a running verify without interrupting the connection.
Had to bump the protocol version differently, we are now 101.
Added verify_can_do_stop_sector() { protocol >= 97 && protocol != 100; }
Also, the return value convention for worker callbacks has changed,
we returned "true/false" for "keep the connection up" in 8.3,
we return 0 for success and <= for failure in 8.4.
Affected: receive_state()
Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
By disabling al-updates one might increase performace. The price for
that is that in case a crashed primary (that had al-updates disabled)
is reintegraded, it will receive a full-resync instead of a bitmap
based resync.
Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
New config option for the disk secition "read-balancing", with
the values: prefer-local, prefer-remote, round-robin, when-congested-remote.
Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
* drbd-8.3:
documentation: Documented detach's --force and disk's --disk-timeout
drbd: Implemented the disk-timeout option
drbd: Force flag for the detach operation
drbd: Allow new IOs while the local disk in in FAILED state
drbd: Bitmap IO functions can not return prematurely if the disk breaks
drbd: Added a kref to bm_aio_ctx
drbd: Hold a reference to ldev while doing meta-data IO
drbd: Keep a reference to the bio until the completion handler finished
drbd: Implemented wait_until_done_or_disk_failure()
drbd: Replaced md_io_mutex by an atomic: md_io_in_use
drbd: moved md_io into mdev
drbd: Immediately allow completion of IOs, that wait for IO completions on a failed disk
drbd: Keep a reference to barrier acked requests
Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
drbdadm already has a --dry-run option, so this option cannot directly be
passed through to drbdsetup. Rename the drbdsetup option to resolve this
conflict.
For backward compatibility, make --dry-run an alias of --tentative.
Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
This is done by introducing drbd_nla_find_nested() which handles the flag
before calling nla_find_nested().
Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
Make it more clear in the flag names which flags are internal to drbd, and
which are not.
The check for mandatory attributes is the only extension visible at the netlink
layer. Attributes with this flag set would look like unknown attributes to
some kernel versions. The netlink layer would ignore them and also skip
consistency checks on the attribute type and legth. To avoid this, we check
for mandatory attributes first, remove the mandatory flag, and then process the
attributes normally.
Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
The 32-bit resync_after netlink field takes a device minor number as
parameter, which is no longer limited to 255. We cannot statically
verify which device numbers are valid, so set the ummer limit to the
highest possible signed 32-bit integer.
Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
This is what it is called in config files and on the command line as
well.
Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
Change the --no-tcp-cork drbdsetup command line option as well as
the no_cork netlink packet.
Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
Change the --no-md-flushes drbdsetup command line option as well as
the no_md_flush netlink packet.
Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
Change the --no-disk-drain drbdsetup command line option as well as
the no_disk_drain netlink packet.
Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
Change the --no-disk-flushes drbdsetup command line option as well as
the no_disk_flush netlink packet.
Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
...and drop explicit typecasts (int)meta_dev_idx < 0.
Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
The 8 byte header finally becomes too small. With the protocol 100 header we
have 16 bit for the volume number, proper 32 bit for the data length, and
32 bit for further extensions in the future.
Previous versions of drbd are using version 80 headers for all packets
short enough for protocol 80. They support both header versions in
worker context, but only version 80 headers in asynchronous context.
For backwards compatibility, continue to use version 80 headers for
short packets before protocol version 100.
From protocol version 100 on, use the same header version for all
packets.
Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
This commit breaks the API again.
Move per-volume former syncer options into disk_conf.
Move per-connection former syncer options into net_conf.
Renamed the remainign sync_conf to res_opts
Syncer settings have been changeable at runtime, so we need to prepare
for these settings to be runtime-changeable in their new home as well.
Introduce new configuration operations, and share the netlink attribute
between "attach" (create new disk) and "disk-opts" (change options).
Same for "connect" and "net-opts".
Some fields cannot be changed at runtime, however.
Introduce a new flag GENLA_F_INVARIANT to be able to trigger on that in
the generated validation and assignment functions.
Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
This greatly simplifies deconfiguration of whole resources.
Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
This adds the new API header and helper files.
Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
Lars Ellenberg
Philipp Reisner
Andreas Gruenbacher
Philipp Marek