mirror of https://github.com/schoebel/mars
334 lines
9.2 KiB
Plaintext
334 lines
9.2 KiB
Plaintext
#
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# MARS configuration
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#
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config MARS
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tristate "storage system MARS (EXPERIMENTAL)"
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depends on BLOCK && HIGH_RES_TIMERS
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default n
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---help---
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Experimental storage System. Only compile as a module!
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config MARS_DEBUG
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bool "enable runtime checks in MARS"
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depends on MARS
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default n
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---help---
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OFF for production systems. ON for testing!
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config MARS_BIGMODULE
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tristate "compile all MARS modules into a single kernel module"
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depends on MARS
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default m
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select MARS_HAVE_BIGMODULE
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---help---
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Normally ON. Switch off only for EXPERIMENTS!
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config MARS_DEFAULT_PORT
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int "port number where MARS is listening"
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depends on MARS
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default 7777
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---help---
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Best practice is to uniformly use the same port number
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in a cluster. Therefore, this is compiletime constant.
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config MARS_MEM_RETRY
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bool "make MARS memory allocation more robust"
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depends on MARS
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default y
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---help---
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Normally ON. Switch only off for systems having very low memory.
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config MARS_LOGFILE
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string "full path to the logfile"
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depends on MARS
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default "/mars/log.txt"
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---help---
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Path to the logfile where all MARS messages go to.
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The logfile must already exist in order to be appended.
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Logiles can be rotated by renaming them and creating
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a new empty file in place of the old one.
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When none exists, messages are either reported to syslog when
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CONFIG_MARS_USE_SYSLOG is set, or else MARS will be qiet.
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config MARS_USE_SYSLOG
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bool "use syslog for messages"
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depends on MARS
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default n
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---help---
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Normally OFF.
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When switched on (and no logfile exists), the syslog
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may get flooded by printk() messages, leading to performance
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problems if remote syslog forwarding is enabled (and possibly
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in other cases). Thus we recommend to prefer file logging.
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When this option is off, the logfile will be used (if one exists).
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config MARS_SCAN_INTERVAL
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int "re-scanning of symlinks in /mars/ (in seconds)"
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depends on MARS
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default 5
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---help---
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May influence the system load; dont use too low nubmers.
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config MARS_PROPAGATE_INTERVAL
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int "network propagation delay of changes in /mars/ (in seconds)"
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depends on MARS
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default 5
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---help---
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May influence the system load; dont use too low nubmers.
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config MARS_SYNC_FLIP_INTERVAL
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int "interrpt sync by logfile update after (seconds)"
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depends on MARS
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default 60
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---help---
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0 = OFF. Normally ON.
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When disabled, application of logfiles may wait for
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a very time, until full sync has finished. As a
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consequence, your /mars/ filesystem may run out
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of space. When enabled, the applied logfiles can
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be deleted, freeing space on /mars/. Therefore,
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will usually want this. However, you may increase
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the time interval to increase throughput in favour
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of latency.
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config MARS_FAST_TRIGGER
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bool "fast internal triggering"
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depends on MARS
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default y
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---help---
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Normally ON. Switch off in case of endless trigger loops
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config MARS_NETIO_TIMEOUT
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int "timeout for remote IO operations (in seconds)"
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depends on MARS
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default 30
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---help---
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In case of network hangs, don't wait forever, but rather
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abort with -ENOTCONN
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when == 0, wait forever (may lead to hanging operations
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similar to NFS hard mounts)
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config MARS_MEM_PREALLOC
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bool "avoid memory fragmentation by preallocation"
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depends on MARS
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default y
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---help---
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Normally ON. Switch off only for EXPERIMENTS!
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config MARS_FAST_FULLSYNC
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bool "decrease network traffic at initial sync"
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depends on MARS
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default y
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---help---
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Normally ON.
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When on, both sides will read the data, compute a md5
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checksum, and compare them. Only in case the checksum
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mismatches, the data will be actually transferred over
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the network. This may increase the IO traffic in favour
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of network traffic. Usually it does no harm to re-read
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the same data twice (only in case of mismatches) over bio
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because RAID controllers will usually cache their data
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for some time. In case of buffered aio reads from filesystems,
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the data is cached by the kernel anyway.
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config MARS_LOADAVG_LIMIT
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bool "stall copy traffic when loadavg gets too high"
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depends on MARS
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default y
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---help---
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Normally ON.
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config MARS_LINEAR_CACHE_SIZE
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int "cache size for linear scans of logfiles (in MB)"
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depends on MARS
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default 64
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---help---
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Setting this to high numbers (or disabling by setting to 0)
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may disturb the application performance, because MARS will
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pollute the page cache with pages from the MARS logfiles.
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Setting this to low numbers will prevent such a pollution,
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at the cost of (sometimes) more IO operations.
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EXCEPTION: when you run MARS on a standalone storage server
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(e.g. exporting devices via iSCSI), you should use high numbers
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here or even disable this feature. THEN (and ONLY THEN)
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you want MARS to use all the memory for its own caching,
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since there is no other application competing for main memory.
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In unsure, take the default of 64.
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#config MARS_HUNG
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# bool "hangup on kernel stacktrace (EXPERIMENTAL!!!)"
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# depends on MARS && MARS_BIGMODULE!=m
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# default n
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# ---help---
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# Normally OFF. Switch on only for EXPERIMENTS!
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config MARS_LOGROT
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bool "allow logrotate during operation"
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depends on MARS
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default y
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---help---
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Normally ON. Switch off only for EXPERIMENTS!
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config MARS_LOGROT_AUTO
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int "automatic logrotate when logfile exceeds size (in GB)"
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depends on MARS_LOGROT
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default 32
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---help---
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You could switch this off by setting to 0. However, deletion
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of really huge logfile can take several minutes, or even substantial
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fractions of hours (depending on the underlying filesystem).
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Thus it is highly recommended to limit the logfile size to some
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reasonable maximum size. Switch only off for experiments!
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config MARS_MIN_SPACE
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bool "check for filesystem overflow in /mars"
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depends on MARS
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default y
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---help---
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Normally ON. Switch off only for EXPERIMENTS!
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config MARS_MIN_SPACE_BASE
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int "free space in /mars/ (hard limit in gigabytes)"
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depends on MARS_MIN_SPACE
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default 8
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---help---
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when this limit is exceeded, transaction logging to /mars/
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will stop. This affects not only write IO to /dev/mars/*,
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but also logfile transfers etc. As a consequence, writes
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on the primary will directly go to the device, and the secondaries
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will be outdated.
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In order to retain full operations, you _need_ to implement
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your own monitoring which _must_ warn you long before this
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hard limit catches you. If it already has caught you, it
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will be too late: you have to recover by hand, e.g. by
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starting a full sync.
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config MARS_MIN_SPACE_PERCENT
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int "free space in /mars/ (hard limit in percent)"
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depends on MARS_MIN_SPACE
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default 0
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---help---
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this limit is in addition to CONFIG_MARS_MIN_SPACE_BASE.
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config MARS_LOGDELETE_AUTO
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int "automatic log-delete when space in /mars/ gets short (in GB)"
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depends on MARS_MIN_SPACE
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default 8
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---help---
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This limit is in addition to CONFIG_MARS_MIN_SPACE_BASE
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and CONFIG_MARS_MIN_SPACE_PERCENT.
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You can switch this off by setting to 0.
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When the limit is hit, MARS tries to delete the eldest logfile,
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when possible, in order to free some space.
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Notice: deleting logfiles on a primary which have not yet
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been transferred to some secondary is possible, but as a
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consequence the secondary may need a full-sync afterwards.
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config MARS_PREFER_SIO
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bool "prefer sio bricks instead of aio"
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depends on MARS
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default n
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---help---
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Normally OFF for production systems.
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Only use as alternative for testing.
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##### mostly obsolete
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config MARS_DUMMY
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tristate "MARS dummy brick"
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depends on MARS && MARS_BIGMODULE!=m
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default m
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---help---
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Experimental storage System.
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config MARS_CHECK
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tristate "MARS check brick"
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depends on MARS && MARS_BIGMODULE!=m
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default m
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---help---
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Experimental storage System.
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config MARS_IF
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tristate "interface to a linux device"
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depends on MARS && MARS_BIGMODULE!=m
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default m
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---help---
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Experimental storage System.
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config MARS_BIO
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tristate "interface to blkdev via kernel BIO"
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depends on MARS && MARS_BIGMODULE!=m
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default m
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---help---
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Experimental storage System.
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config MARS_AIO
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tristate "interface to a linux file (Asynchronous IO)"
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depends on MARS && MARS_BIGMODULE!=m
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default m
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---help---
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Experimental storage System.
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config MARS_SIO
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tristate "interface to a linux file, synchronous (currently unused)"
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depends on MARS && MARS_BIGMODULE!=m
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default m
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---help---
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Experimental storage System.
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config MARS_BUF
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tristate "buffer brick (currently unused)"
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depends on MARS && MARS_BIGMODULE!=m
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default m
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---help---
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Experimental storage System.
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config MARS_USEBUF
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tristate "usebuf brick (currently unused)"
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depends on MARS && MARS_BIGMODULE!=m
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default m
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---help---
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Experimental storage System.
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config MARS_TRANS_LOGGER
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tristate "transaction logger"
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depends on MARS && MARS_BIGMODULE!=m
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default m
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---help---
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Experimental storage System.
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config MARS_SERVER
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tristate "server brick"
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depends on MARS && MARS_BIGMODULE!=m
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default m
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---help---
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Experimental storage System.
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config MARS_CLIENT
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tristate "client brick"
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depends on MARS && MARS_BIGMODULE!=m
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default m
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---help---
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Experimental storage System.
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config MARS_COPY
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tristate "copy brick"
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depends on MARS && MARS_BIGMODULE!=m
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default m
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---help---
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Experimental storage System.
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config MARS_LIGHT
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tristate "MARS Light main (protoype, will be replaced)"
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depends on MARS && MARS_BIGMODULE!=m
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default m
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---help---
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Experimental storage System.
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# the following is used as an internal proprocessor symbol
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config MARS_HAVE_BIGMODULE
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bool
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