mirror of
https://github.com/schoebel/mars
synced 2024-12-24 23:52:46 +00:00
422 lines
13 KiB
Plaintext
422 lines
13 KiB
Plaintext
#
|
|
# MARS configuration
|
|
#
|
|
|
|
config MARS
|
|
tristate "block storage replication MARS"
|
|
depends on m
|
|
depends on BLOCK && PROC_SYSCTL && HIGH_RES_TIMERS
|
|
default n
|
|
select LZO_COMPRESS
|
|
select LZO_DECOMPRESS
|
|
select LZ4_COMPRESS
|
|
select LZ4_DECOMPRESS
|
|
select ZLIB_INFLATE
|
|
select ZLIB_DEFLATE
|
|
select CRYPTO_MD5
|
|
select CRYPTO_CRC32
|
|
select CRYPTO_CRC32C
|
|
select CRYPTO_SHA1
|
|
---help---
|
|
See https://github.com/schoebel/mars/docu/
|
|
Only compile as a module!
|
|
|
|
config MARS_BENCHMARK
|
|
bool "rough measurement of digest and compression algorithms"
|
|
depends on MARS
|
|
default y
|
|
---help---
|
|
Upon modprobe mars, display some rough measurements in
|
|
nanoseconds. Note that results may depend on the compressibility
|
|
of test data. Thus take the results with a grain of salt
|
|
(similarly to BogoMIPS).
|
|
If unsure, say Y here.
|
|
|
|
config MARS_CHECKS
|
|
bool "enable simple runtime checks in MARS"
|
|
depends on MARS
|
|
default y
|
|
---help---
|
|
These checks should be rather lightweight. Use them
|
|
for beta testing and for production systems where
|
|
safety is more important than performance.
|
|
In case of bugs in the reference counting, an automatic repair
|
|
is attempted, which lowers the risk of memory corruptions.
|
|
Disable only if you need the absolutely last grain of
|
|
performance.
|
|
If unsure, say Y here.
|
|
|
|
config MARS_DEBUG
|
|
bool "enable full runtime checks and some tracing in MARS"
|
|
depends on MARS
|
|
default n
|
|
---help---
|
|
Some of these checks and some additional error tracing may
|
|
consume noticable amounts of memory.
|
|
OFF for production systems. ON for testing!
|
|
|
|
config MARS_DEBUG_DEFAULT
|
|
bool "turn on debug messages by default (may flood the logfiles)"
|
|
depends on MARS_DEBUG
|
|
default n
|
|
---help---
|
|
normally OFF
|
|
|
|
config MARS_DEBUG_MEM
|
|
bool "debug memory operations"
|
|
depends on MARS_DEBUG
|
|
default n
|
|
---help---
|
|
This adds considerable space and time overhead, but catches
|
|
many errors (including some that are not caught by kmemleak).
|
|
Use only for development and thorough testing!
|
|
|
|
config MARS_DEBUG_MEM_STRONG
|
|
bool "intensified debugging of memory operations"
|
|
depends on MARS_DEBUG_MEM
|
|
default y
|
|
---help---
|
|
Trace all block allocations, find more errors.
|
|
Adds some overhead.
|
|
Use for debugging of new bricks or for intensified
|
|
regression testing.
|
|
|
|
config MARS_DEBUG_ORDER0
|
|
bool "also debug order0 operations"
|
|
depends on MARS_DEBUG_MEM
|
|
default n
|
|
---help---
|
|
Turn even order 0 allocations into order 1 ones and provoke
|
|
heavy memory fragmentation problems from the buddy allocator,
|
|
but catch some additional memory problems.
|
|
Use only if you know what you are doing!
|
|
Normally OFF.
|
|
|
|
config MARS_DEFAULT_PORT
|
|
int "port number where MARS is listening"
|
|
depends on MARS
|
|
default 7777
|
|
---help---
|
|
Best practice is to uniformly use the same port number
|
|
in a cluster. Therefore, this is a compiletime constant.
|
|
You may override this at insmod time via the mars_port= parameter.
|
|
|
|
config MARS_SEPARATE_PORTS
|
|
bool "use separate port numbers for traffic shaping"
|
|
depends on MARS
|
|
default y
|
|
---help---
|
|
When enabled, the following port assignments will be used:
|
|
|
|
CONFIG_MARS_DEFAULT_PORT : updates of symlinks
|
|
CONFIG_MARS_DEFAULT_PORT + 1 : replication of logfiles
|
|
CONFIG_MARS_DEFAULT_PORT + 2 : (initial) sync traffic
|
|
|
|
As a consequence, external traffic shaping may be used to
|
|
individually control the network speed for different types
|
|
of traffic.
|
|
|
|
Please don't hinder the symlink updates in any way -- they are
|
|
most vital, and they produce no mass traffic at all
|
|
(it's only some kind of meta-information traffic).
|
|
|
|
Say Y if you have a big datacenter.
|
|
Say N if you cannot afford a bigger hole in your firefall.
|
|
If unsure, say Y.
|
|
|
|
|
|
config MARS_IPv4_TOS
|
|
bool "use TOS / DSCP in IPv4"
|
|
depends on MARS_SEPARATE_PORTS
|
|
default y
|
|
---help---
|
|
Tag IP traffic differently for different ports.
|
|
In certain private networks, this can improve certain
|
|
network bottlenecks.
|
|
|
|
config MARS_MEM_RETRY
|
|
bool "make MARS memory allocation more robust"
|
|
depends on MARS
|
|
default y
|
|
---help---
|
|
Normally ON. Switch only off for systems having very low memory.
|
|
|
|
config MARS_LOGDIR
|
|
string "absolute path to the logging directory"
|
|
depends on MARS
|
|
default "/mars"
|
|
---help---
|
|
Path to the directory where all MARS messages will reside.
|
|
Usually this is equal to the global /mars directory.
|
|
|
|
Logfiles and status files obey the following naming conventions:
|
|
0.debug.log
|
|
1.info.log
|
|
2.warn.log
|
|
3.error.log
|
|
4.fatal.log
|
|
5.total.log
|
|
Logfiles must already exist in order to be appended.
|
|
Logiles can be rotated by renaming them and creating
|
|
a new empty file in place of the old one.
|
|
|
|
Status files follow the same rules, but .log is replaced
|
|
by .status, and they are created automatically. Their content
|
|
is however limited to a few seconds or minutes.
|
|
|
|
config MARS_ROLLOVER_INTERVAL
|
|
int "rollover time of logging status files (in seconds)"
|
|
depends on MARS
|
|
default 3
|
|
---help---
|
|
May influence the system load; dont use too low nubmers.
|
|
|
|
config MARS_SCAN_INTERVAL
|
|
int "re-scanning of symlinks in /mars/ (in seconds)"
|
|
depends on MARS
|
|
default 5
|
|
---help---
|
|
May influence the system load; dont use too low nubmers.
|
|
|
|
config MARS_PROPAGATE_INTERVAL
|
|
int "network propagation delay of changes in /mars/ (in seconds)"
|
|
depends on MARS
|
|
default 5
|
|
---help---
|
|
May influence the system load; dont use too low nubmers.
|
|
|
|
config MARS_SYNC_FLIP_INTERVAL
|
|
int "interrpt sync by logfile update after (seconds)"
|
|
depends on MARS
|
|
default 60
|
|
---help---
|
|
0 = OFF. Normally ON.
|
|
When disabled, application of logfiles may wait for
|
|
a very time, until full sync has finished. As a
|
|
consequence, your /mars/ filesystem may run out
|
|
of space. When enabled, the applied logfiles can
|
|
be deleted, freeing space on /mars/. Therefore,
|
|
will usually want this. However, you may increase
|
|
the time interval to increase throughput in favour
|
|
of latency.
|
|
|
|
config MARS_NETIO_TIMEOUT
|
|
int "timeout for remote IO operations (in seconds)"
|
|
depends on MARS
|
|
default 30
|
|
---help---
|
|
In case of network hangs, don't wait forever, but rather
|
|
abort with -ENOTCONN
|
|
when == 0, wait forever (may lead to hanging operations
|
|
similar to NFS hard mounts)
|
|
|
|
config MARS_MEM_PREALLOC
|
|
bool "avoid memory fragmentation by preallocation"
|
|
depends on MARS
|
|
default y
|
|
---help---
|
|
Normally ON. Switch off only for EXPERIMENTS!
|
|
|
|
config MARS_FAST_FULLSYNC
|
|
bool "decrease network traffic at initial sync"
|
|
depends on MARS
|
|
default y
|
|
---help---
|
|
Normally ON.
|
|
When on, both sides will read the data, compute a md5
|
|
checksum, and compare them. Only in case the checksum
|
|
mismatches, the data will be actually transferred over
|
|
the network. This may increase the IO traffic in favour
|
|
of network traffic. Usually it does no harm to re-read
|
|
the same data twice (only in case of mismatches) over bio
|
|
because RAID controllers will usually cache their data
|
|
for some time. In case of buffered aio reads from filesystems,
|
|
the data is cached by the kernel anyway.
|
|
|
|
config MARS_SHOW_CONNECTIONS
|
|
bool "show connection status symlinks"
|
|
depends on MARS
|
|
default n
|
|
---help---
|
|
Normally OFF.
|
|
|
|
When enabled, the status of all current network connections is
|
|
written to /mars/resource-$resource/local-$host/connect-*
|
|
showing the current status of all network connections by
|
|
the following encoding:
|
|
|
|
-1 = connection is closed (not intended to start)
|
|
0 = connection is interrupted / not established
|
|
1 = connection is established at TCP level
|
|
|
|
Warning! the symlinks are not deleted by the kernel. You have
|
|
to cleanup old symlinks by yourself in userspace.
|
|
|
|
When you forget the cleanup in regular intervals, you may
|
|
end up with thoundands of symlinks accumulating in the
|
|
/mars/resource-$resource/local-$host/ directory over a
|
|
longer time.
|
|
|
|
If unsure, say N here.
|
|
|
|
config MARS_LOGROT
|
|
bool "allow logrotate during operation"
|
|
depends on MARS
|
|
default y
|
|
---help---
|
|
Normally ON. Switch off only for EXPERIMENTS!
|
|
|
|
config MARS_MIN_SPACE_4
|
|
int "absolutely necessary free space in /mars/ (hard limit in GB)"
|
|
depends on MARS
|
|
default 2
|
|
---help---
|
|
HARDEST EMERGENCY LIMIT
|
|
|
|
When free space in /mars/ drops under this limit,
|
|
transaction logging to /mars/ will stop at all,
|
|
even at all primary resources. All IO will directly go to the
|
|
underlying raw devices. The transaction logfile sequence numbers
|
|
will be disrupted, deliberately leaving holes in the sequence.
|
|
|
|
This is a last-resort desperate action of the kernel.
|
|
|
|
As a consequence, all secodaries will have no chance to
|
|
replay at that gap, even if they got the logfiles.
|
|
The secondaries will stop at the gap, left in an outdated,
|
|
but logically consistent state.
|
|
|
|
After the problem has been fixed, the secondaries must
|
|
start a full-sync in order to continue replication at the
|
|
recent state.
|
|
|
|
This is the hardest measure the kernel can take in order
|
|
to TRY to continue undisrupted operation at the primary side.
|
|
|
|
In general, you should avoid such situations at the admin level.
|
|
|
|
Please implement your own monitoring at the admin level, which warns
|
|
you and/or takes appropriate countermeasures much earlier.
|
|
Never rely on this emergency feature!
|
|
|
|
config MARS_MIN_SPACE_3
|
|
int "free space in /mars/ for primary logfiles (additional limit in GB)"
|
|
depends on MARS
|
|
default 2
|
|
---help---
|
|
MEDIUM EMERGENCY LIMIT
|
|
|
|
When free space in /mars/ drops under
|
|
MARS_MIN_SPACE_4 + MARS_MIN_SPACE_3,
|
|
elder transaction logfiles will be deleted at primary resources.
|
|
|
|
As a consequence, the secondaries may no longer be able to
|
|
get a consecute series of copies of logfiles.
|
|
As a result, they may get stuck somewhere inbetween at an
|
|
outdated, but logically consistent state.
|
|
|
|
This is a desperate action of the kernel.
|
|
|
|
After the problem has been fixed, some secondaries may need to
|
|
start a full-sync in order to continue replication at the
|
|
recent state.
|
|
|
|
In general, you should avoid such situations at the admin level.
|
|
|
|
Please implement your own monitoring at the admin level, which warns
|
|
you and/or takes appropriate countermeasures much earlier.
|
|
Never rely on this emergency feature!
|
|
|
|
config MARS_MIN_SPACE_2
|
|
int "free space in /mars/ for secondary logfiles (additional limit in GB)"
|
|
depends on MARS
|
|
default 2
|
|
---help---
|
|
MEDIUM EMERGENCY LIMIT
|
|
|
|
When free space in /mars/ drops under
|
|
MARS_MIN_SPACE_4 + MARS_MIN_SPACE_3 + MARS_MIN_SPACE_2,
|
|
elder transaction logfiles will be deleted at secondary resources.
|
|
|
|
As a consequence, some local secondary resources
|
|
may get stuck somewhere inbetween at an
|
|
outdated, but logically consistent state.
|
|
|
|
This is a desperate action of the kernel.
|
|
|
|
After the problem has been fixed and the free space becomes
|
|
larger than MARS_MIN_SPACE_4 + MARS_MIN_SPACE_3 + MARS_MIN_SPACE_2
|
|
+ MARS_MIN_SPACE_2, the secondary tries to fetch the missing
|
|
logfiles from the primary again.
|
|
|
|
However, if the necessary logfiles have been deleted at the
|
|
primary side in the meantime, this may fail.
|
|
|
|
In general, you should avoid such situations at the admin level.
|
|
|
|
Please implement your own monitoring at the admin level, which warns
|
|
you and/or takes appropriate countermeasures much earlier.
|
|
Never rely on this emergency feature!
|
|
|
|
config MARS_MIN_SPACE_1
|
|
int "free space in /mars/ for replication (additional limit in GB)"
|
|
depends on MARS
|
|
default 2
|
|
---help---
|
|
LOWEST EMERGENCY LIMIT
|
|
|
|
When free space in /mars/ drops under MARS_MIN_SPACE_4
|
|
+ MARS_MIN_SPACE_3 + MARS_MIN_SPACE_2 + MARS_MIN_SPACE_1,
|
|
fetching of transaction logfiles will stop at local secondary
|
|
resources.
|
|
|
|
As a consequence, some local secondary resources
|
|
may get stuck somewhere inbetween at an
|
|
outdated, but logically consistent state.
|
|
|
|
This is a desperate action of the kernel.
|
|
|
|
After the problem has been fixed and the free space becomes
|
|
larger than MARS_MIN_SPACE_4 + MARS_MIN_SPACE_3 + MARS_MIN_SPACE_2
|
|
+ MARS_MIN_SPACE_2, the secondary will continue fetching its
|
|
copy of logfiles from the primary side.
|
|
|
|
In general, you should avoid such situations at the admin level.
|
|
|
|
Please implement your own monitoring at the admin level, which warns
|
|
you and/or takes appropriate countermeasures much earlier.
|
|
Never rely on this emergency feature!
|
|
|
|
config MARS_MIN_SPACE_0
|
|
int "total space needed in /mars/ for (additional limit in GB)"
|
|
depends on MARS
|
|
default 12
|
|
---help---
|
|
Operational pre-requirement.
|
|
|
|
In order to use MARS, the total space available in /mars/ must
|
|
be at least MARS_MIN_SPACE_4 + MARS_MIN_SPACE_3 + MARS_MIN_SPACE_2
|
|
+ MARS_MIN_SPACE_1 + MARS_MIN_SPACE_0.
|
|
|
|
If you cannot afford that amount of storage space, please use
|
|
DRBD in place of MARS.
|
|
|
|
config MARS_LOGROT_AUTO
|
|
int "automatic logrotate when logfile exceeds size (in GB)"
|
|
depends on MARS_LOGROT
|
|
default 32
|
|
---help---
|
|
You could switch this off by setting to 0. However, deletion
|
|
of really huge logfiles can take several minutes, or even substantial
|
|
fractions of hours (depending on the underlying filesystem).
|
|
Thus it is highly recommended to limit the logfile size to some
|
|
reasonable maximum size. Switch only off for experiments!
|
|
|
|
config MARS_PREFER_SIO
|
|
bool "prefer sio bricks instead of aio"
|
|
depends on MARS
|
|
default n
|
|
---help---
|
|
Normally OFF for production systems.
|
|
Only use as alternative for testing.
|