OpenCloudOS-Kernel/include/linux/drbd_limits.h

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/*
drbd_limits.h
This file is part of DRBD by Philipp Reisner and Lars Ellenberg.
*/
/*
* Our current limitations.
* Some of them are hard limits,
* some of them are arbitrary range limits, that make it easier to provide
* feedback about nonsense settings for certain configurable values.
*/
#ifndef DRBD_LIMITS_H
#define DRBD_LIMITS_H 1
#define DEBUG_RANGE_CHECK 0
#define DRBD_MINOR_COUNT_MIN 1
#define DRBD_MINOR_COUNT_MAX 255
#define DRBD_MINOR_COUNT_DEF 32
#define DRBD_MINOR_COUNT_SCALE '1'
#define DRBD_VOLUME_MAX 65535
#define DRBD_DIALOG_REFRESH_MIN 0
#define DRBD_DIALOG_REFRESH_MAX 600
#define DRBD_DIALOG_REFRESH_SCALE '1'
/* valid port number */
#define DRBD_PORT_MIN 1
#define DRBD_PORT_MAX 0xffff
#define DRBD_PORT_SCALE '1'
/* startup { */
/* if you want more than 3.4 days, disable */
#define DRBD_WFC_TIMEOUT_MIN 0
#define DRBD_WFC_TIMEOUT_MAX 300000
#define DRBD_WFC_TIMEOUT_DEF 0
#define DRBD_WFC_TIMEOUT_SCALE '1'
#define DRBD_DEGR_WFC_TIMEOUT_MIN 0
#define DRBD_DEGR_WFC_TIMEOUT_MAX 300000
#define DRBD_DEGR_WFC_TIMEOUT_DEF 0
#define DRBD_DEGR_WFC_TIMEOUT_SCALE '1'
#define DRBD_OUTDATED_WFC_TIMEOUT_MIN 0
#define DRBD_OUTDATED_WFC_TIMEOUT_MAX 300000
#define DRBD_OUTDATED_WFC_TIMEOUT_DEF 0
#define DRBD_OUTDATED_WFC_TIMEOUT_SCALE '1'
/* }*/
/* net { */
/* timeout, unit centi seconds
* more than one minute timeout is not useful */
#define DRBD_TIMEOUT_MIN 1
#define DRBD_TIMEOUT_MAX 600
#define DRBD_TIMEOUT_DEF 60 /* 6 seconds */
#define DRBD_TIMEOUT_SCALE '1'
/* If backing disk takes longer than disk_timeout, mark the disk as failed */
#define DRBD_DISK_TIMEOUT_MIN 0 /* 0 = disabled */
#define DRBD_DISK_TIMEOUT_MAX 6000 /* 10 Minutes */
#define DRBD_DISK_TIMEOUT_DEF 0 /* disabled */
#define DRBD_DISK_TIMEOUT_SCALE '1'
/* active connection retries when C_WF_CONNECTION */
#define DRBD_CONNECT_INT_MIN 1
#define DRBD_CONNECT_INT_MAX 120
#define DRBD_CONNECT_INT_DEF 10 /* seconds */
#define DRBD_CONNECT_INT_SCALE '1'
/* keep-alive probes when idle */
#define DRBD_PING_INT_MIN 1
#define DRBD_PING_INT_MAX 120
#define DRBD_PING_INT_DEF 10
#define DRBD_PING_INT_SCALE '1'
/* timeout for the ping packets.*/
#define DRBD_PING_TIMEO_MIN 1
#define DRBD_PING_TIMEO_MAX 300
#define DRBD_PING_TIMEO_DEF 5
#define DRBD_PING_TIMEO_SCALE '1'
/* max number of write requests between write barriers */
#define DRBD_MAX_EPOCH_SIZE_MIN 1
#define DRBD_MAX_EPOCH_SIZE_MAX 20000
#define DRBD_MAX_EPOCH_SIZE_DEF 2048
#define DRBD_MAX_EPOCH_SIZE_SCALE '1'
/* I don't think that a tcp send buffer of more than 10M is useful */
#define DRBD_SNDBUF_SIZE_MIN 0
#define DRBD_SNDBUF_SIZE_MAX (10<<20)
#define DRBD_SNDBUF_SIZE_DEF 0
#define DRBD_SNDBUF_SIZE_SCALE '1'
#define DRBD_RCVBUF_SIZE_MIN 0
#define DRBD_RCVBUF_SIZE_MAX (10<<20)
#define DRBD_RCVBUF_SIZE_DEF 0
#define DRBD_RCVBUF_SIZE_SCALE '1'
/* @4k PageSize -> 128kB - 512MB */
#define DRBD_MAX_BUFFERS_MIN 32
#define DRBD_MAX_BUFFERS_MAX 131072
#define DRBD_MAX_BUFFERS_DEF 2048
#define DRBD_MAX_BUFFERS_SCALE '1'
/* @4k PageSize -> 4kB - 512MB */
#define DRBD_UNPLUG_WATERMARK_MIN 1
#define DRBD_UNPLUG_WATERMARK_MAX 131072
#define DRBD_UNPLUG_WATERMARK_DEF (DRBD_MAX_BUFFERS_DEF/16)
#define DRBD_UNPLUG_WATERMARK_SCALE '1'
/* 0 is disabled.
* 200 should be more than enough even for very short timeouts */
#define DRBD_KO_COUNT_MIN 0
#define DRBD_KO_COUNT_MAX 200
#define DRBD_KO_COUNT_DEF 7
#define DRBD_KO_COUNT_SCALE '1'
/* } */
/* syncer { */
/* FIXME allow rate to be zero? */
#define DRBD_RESYNC_RATE_MIN 1
/* channel bonding 10 GbE, or other hardware */
#define DRBD_RESYNC_RATE_MAX (4 << 20)
#define DRBD_RESYNC_RATE_DEF 250
#define DRBD_RESYNC_RATE_SCALE 'k' /* kilobytes */
#define DRBD_AL_EXTENTS_MIN 67
/* we use u16 as "slot number", (u16)~0 is "FREE".
* If you use >= 292 kB on-disk ring buffer,
* this is the maximum you can use: */
#define DRBD_AL_EXTENTS_MAX 0xfffe
#define DRBD_AL_EXTENTS_DEF 1237
#define DRBD_AL_EXTENTS_SCALE '1'
#define DRBD_MINOR_NUMBER_MIN -1
#define DRBD_MINOR_NUMBER_MAX ((1 << 20) - 1)
#define DRBD_MINOR_NUMBER_DEF -1
#define DRBD_MINOR_NUMBER_SCALE '1'
/* } */
/* drbdsetup XY resize -d Z
* you are free to reduce the device size to nothing, if you want to.
* the upper limit with 64bit kernel, enough ram and flexible meta data
* is 1 PiB, currently. */
/* DRBD_MAX_SECTORS */
#define DRBD_DISK_SIZE_MIN 0
#define DRBD_DISK_SIZE_MAX (1 * (2LLU << 40))
#define DRBD_DISK_SIZE_DEF 0 /* = disabled = no user size... */
#define DRBD_DISK_SIZE_SCALE 's' /* sectors */
#define DRBD_ON_IO_ERROR_DEF EP_DETACH
#define DRBD_FENCING_DEF FP_DONT_CARE
#define DRBD_AFTER_SB_0P_DEF ASB_DISCONNECT
#define DRBD_AFTER_SB_1P_DEF ASB_DISCONNECT
#define DRBD_AFTER_SB_2P_DEF ASB_DISCONNECT
#define DRBD_RR_CONFLICT_DEF ASB_DISCONNECT
#define DRBD_ON_NO_DATA_DEF OND_IO_ERROR
#define DRBD_ON_CONGESTION_DEF OC_BLOCK
#define DRBD_READ_BALANCING_DEF RB_PREFER_LOCAL
#define DRBD_MAX_BIO_BVECS_MIN 0
#define DRBD_MAX_BIO_BVECS_MAX 128
#define DRBD_MAX_BIO_BVECS_DEF 0
#define DRBD_MAX_BIO_BVECS_SCALE '1'
#define DRBD_C_PLAN_AHEAD_MIN 0
#define DRBD_C_PLAN_AHEAD_MAX 300
#define DRBD_C_PLAN_AHEAD_DEF 20
#define DRBD_C_PLAN_AHEAD_SCALE '1'
#define DRBD_C_DELAY_TARGET_MIN 1
#define DRBD_C_DELAY_TARGET_MAX 100
#define DRBD_C_DELAY_TARGET_DEF 10
#define DRBD_C_DELAY_TARGET_SCALE '1'
#define DRBD_C_FILL_TARGET_MIN 0
#define DRBD_C_FILL_TARGET_MAX (1<<20) /* 500MByte in sec */
#define DRBD_C_FILL_TARGET_DEF 100 /* Try to place 50KiB in socket send buffer during resync */
#define DRBD_C_FILL_TARGET_SCALE 's' /* sectors */
#define DRBD_C_MAX_RATE_MIN 250
#define DRBD_C_MAX_RATE_MAX (4 << 20)
#define DRBD_C_MAX_RATE_DEF 102400
#define DRBD_C_MAX_RATE_SCALE 'k' /* kilobytes */
#define DRBD_C_MIN_RATE_MIN 0
#define DRBD_C_MIN_RATE_MAX (4 << 20)
#define DRBD_C_MIN_RATE_DEF 250
#define DRBD_C_MIN_RATE_SCALE 'k' /* kilobytes */
#define DRBD_CONG_FILL_MIN 0
#define DRBD_CONG_FILL_MAX (10<<21) /* 10GByte in sectors */
#define DRBD_CONG_FILL_DEF 0
#define DRBD_CONG_FILL_SCALE 's' /* sectors */
#define DRBD_CONG_EXTENTS_MIN DRBD_AL_EXTENTS_MIN
#define DRBD_CONG_EXTENTS_MAX DRBD_AL_EXTENTS_MAX
#define DRBD_CONG_EXTENTS_DEF DRBD_AL_EXTENTS_DEF
#define DRBD_CONG_EXTENTS_SCALE DRBD_AL_EXTENTS_SCALE
#define DRBD_PROTOCOL_DEF DRBD_PROT_C
#define DRBD_DISK_BARRIER_DEF 0
#define DRBD_DISK_FLUSHES_DEF 1
#define DRBD_DISK_DRAIN_DEF 1
#define DRBD_MD_FLUSHES_DEF 1
#define DRBD_TCP_CORK_DEF 1
#define DRBD_AL_UPDATES_DEF 1
drbd: when receiving P_TRIM, zero-out partial unaligned chunks 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>
2016-06-14 06:26:20 +08:00
/* We used to ignore the discard_zeroes_data setting.
* To not change established (and expected) behaviour,
* by default assume that, for discard_zeroes_data=0,
* we can make that an effective discard_zeroes_data=1,
* if we only explicitly zero-out unaligned partial chunks. */
#define DRBD_DISCARD_ZEROES_IF_ALIGNED 1
#define DRBD_ALLOW_TWO_PRIMARIES_DEF 0
#define DRBD_ALWAYS_ASBP_DEF 0
#define DRBD_USE_RLE_DEF 1
#define DRBD_CSUMS_AFTER_CRASH_ONLY_DEF 0
#define DRBD_AL_STRIPES_MIN 1
#define DRBD_AL_STRIPES_MAX 1024
#define DRBD_AL_STRIPES_DEF 1
#define DRBD_AL_STRIPES_SCALE '1'
#define DRBD_AL_STRIPE_SIZE_MIN 4
#define DRBD_AL_STRIPE_SIZE_MAX 16777216
#define DRBD_AL_STRIPE_SIZE_DEF 32
#define DRBD_AL_STRIPE_SIZE_SCALE 'k' /* kilobytes */
#define DRBD_SOCKET_CHECK_TIMEO_MIN 0
#define DRBD_SOCKET_CHECK_TIMEO_MAX DRBD_PING_TIMEO_MAX
#define DRBD_SOCKET_CHECK_TIMEO_DEF 0
#define DRBD_SOCKET_CHECK_TIMEO_SCALE '1'
#define DRBD_RS_DISCARD_GRANULARITY_MIN 0
#define DRBD_RS_DISCARD_GRANULARITY_MAX (1<<20) /* 1MiByte */
#define DRBD_RS_DISCARD_GRANULARITY_DEF 0 /* disabled by default */
#define DRBD_RS_DISCARD_GRANULARITY_SCALE '1' /* bytes */
#endif