include/linux/drbd_limits.h

   1 /*
   2   drbd_limits.h
   3   This file is part of DRBD by Philipp Reisner and Lars Ellenberg.
   4 */
   5
   6 /*
   7  * Our current limitations.
   8  * Some of them are hard limits,
   9  * some of them are arbitrary range limits, that make it easier to provide
  10  * feedback about nonsense settings for certain configurable values.
  11  */
  12
  13 #ifndef DRBD_LIMITS_H
  14 #define DRBD_LIMITS_H 1
  15
  16 #define DEBUG_RANGE_CHECK 0
  17
  18 #define DRBD_MINOR_COUNT_MIN 1
  19 #define DRBD_MINOR_COUNT_MAX 256
  20 #define DRBD_MINOR_COUNT_DEF 32
  21
  22 #define DRBD_VOLUME_MAX 65535
  23
  24 #define DRBD_DIALOG_REFRESH_MIN 0
  25 #define DRBD_DIALOG_REFRESH_MAX 600
  26
  27 /* valid port number */
  28 #define DRBD_PORT_MIN 1
  29 #define DRBD_PORT_MAX 0xffff
  30
  31 /* startup { */
  32   /* if you want more than 3.4 days, disable */
  33 #define DRBD_WFC_TIMEOUT_MIN 0
  34 #define DRBD_WFC_TIMEOUT_MAX 300000
  35 #define DRBD_WFC_TIMEOUT_DEF 0
  36
  37 #define DRBD_DEGR_WFC_TIMEOUT_MIN 0
  38 #define DRBD_DEGR_WFC_TIMEOUT_MAX 300000
  39 #define DRBD_DEGR_WFC_TIMEOUT_DEF 0
  40
  41 #define DRBD_OUTDATED_WFC_TIMEOUT_MIN 0
  42 #define DRBD_OUTDATED_WFC_TIMEOUT_MAX 300000
  43 #define DRBD_OUTDATED_WFC_TIMEOUT_DEF 0
  44 /* }*/
  45
  46 /* net { */
  47   /* timeout, unit centi seconds
  48    * more than one minute timeout is not useful */
  49 #define DRBD_TIMEOUT_MIN 1
  50 #define DRBD_TIMEOUT_MAX 600
  51 #define DRBD_TIMEOUT_DEF 60       /* 6 seconds */
  52
  53  /* If backing disk takes longer than disk_timeout, mark the disk as failed */
  54 #define DRBD_DISK_TIMEOUT_MIN 0    /* 0 = disabled */
  55 #define DRBD_DISK_TIMEOUT_MAX 6000 /* 10 Minutes */
  56 #define DRBD_DISK_TIMEOUT_DEF 0    /* disabled */
  57 #define DRBD_DISK_TIMEOUT_SCALE '1'
  58
  59   /* active connection retries when C_WF_CONNECTION */
  60 #define DRBD_CONNECT_INT_MIN 1
  61 #define DRBD_CONNECT_INT_MAX 120
  62 #define DRBD_CONNECT_INT_DEF 10   /* seconds */
  63
  64   /* keep-alive probes when idle */
  65 #define DRBD_PING_INT_MIN 1
  66 #define DRBD_PING_INT_MAX 120
  67 #define DRBD_PING_INT_DEF 10
  68
  69  /* timeout for the ping packets.*/
  70 #define DRBD_PING_TIMEO_MIN  1
  71 #define DRBD_PING_TIMEO_MAX  300
  72 #define DRBD_PING_TIMEO_DEF  5
  73
  74   /* max number of write requests between write barriers */
  75 #define DRBD_MAX_EPOCH_SIZE_MIN 1
  76 #define DRBD_MAX_EPOCH_SIZE_MAX 20000
  77 #define DRBD_MAX_EPOCH_SIZE_DEF 2048
  78
  79   /* I don't think that a tcp send buffer of more than 10M is useful */
  80 #define DRBD_SNDBUF_SIZE_MIN  0
  81 #define DRBD_SNDBUF_SIZE_MAX  (10<<20)
  82 #define DRBD_SNDBUF_SIZE_DEF  0
  83
  84 #define DRBD_RCVBUF_SIZE_MIN  0
  85 #define DRBD_RCVBUF_SIZE_MAX  (10<<20)
  86 #define DRBD_RCVBUF_SIZE_DEF  0
  87
  88   /* @4k PageSize -> 128kB - 512MB */
  89 #define DRBD_MAX_BUFFERS_MIN  32
  90 #define DRBD_MAX_BUFFERS_MAX  131072
  91 #define DRBD_MAX_BUFFERS_DEF  2048
  92
  93   /* @4k PageSize -> 4kB - 512MB */
  94 #define DRBD_UNPLUG_WATERMARK_MIN  1
  95 #define DRBD_UNPLUG_WATERMARK_MAX  131072
  96 #define DRBD_UNPLUG_WATERMARK_DEF (DRBD_MAX_BUFFERS_DEF/16)
  97
  98   /* 0 is disabled.
  99    * 200 should be more than enough even for very short timeouts */
 100 #define DRBD_KO_COUNT_MIN  0
 101 #define DRBD_KO_COUNT_MAX  200
 102 #define DRBD_KO_COUNT_DEF  0
 103 /* } */
 104
 105 /* syncer { */
 106   /* FIXME allow rate to be zero? */
 107 #define DRBD_RESYNC_RATE_MIN 1
 108 /* channel bonding 10 GbE, or other hardware */
 109 #define DRBD_RESYNC_RATE_MAX (4 << 20)
 110 #define DRBD_RESYNC_RATE_DEF 250
 111 #define DRBD_RESYNC_RATE_SCALE 'k'  /* kilobytes */
 112
 113   /* less than 7 would hit performance unnecessarily.
 114    * 919 slots context information per transaction,
 115    * 32k activity log, 4k transaction size,
 116    * one transaction in flight:
 117    * 919 * 7 = 6433 */
 118 #define DRBD_AL_EXTENTS_MIN  7
 119 #define DRBD_AL_EXTENTS_MAX  6433
 120 #define DRBD_AL_EXTENTS_DEF  127
 121
 122 #define DRBD_MINOR_NUMBER_MIN  -1
 123 #define DRBD_MINOR_NUMBER_MAX  (1<<30)
 124 #define DRBD_MINOR_NUMBER_DEF  -1
 125 #define DRBD_MINOR_NUMBER_SCALE '1'
 126
 127 /* } */
 128
 129 /* drbdsetup XY resize -d Z
 130  * you are free to reduce the device size to nothing, if you want to.
 131  * the upper limit with 64bit kernel, enough ram and flexible meta data
 132  * is 1 PiB, currently. */
 133 /* DRBD_MAX_SECTORS */
 134 #define DRBD_DISK_SIZE_MIN  0
 135 #define DRBD_DISK_SIZE_MAX  (1 * (2LLU << 40))
 136 #define DRBD_DISK_SIZE_DEF  0 /* = disabled = no user size... */
 137 #define DRBD_DISK_SIZE_SCALE 's'  /* sectors */
 138
 139 #define DRBD_ON_IO_ERROR_DEF EP_DETACH
 140 #define DRBD_FENCING_DEF FP_DONT_CARE
 141 #define DRBD_AFTER_SB_0P_DEF ASB_DISCONNECT
 142 #define DRBD_AFTER_SB_1P_DEF ASB_DISCONNECT
 143 #define DRBD_AFTER_SB_2P_DEF ASB_DISCONNECT
 144 #define DRBD_RR_CONFLICT_DEF ASB_DISCONNECT
 145 #define DRBD_ON_NO_DATA_DEF OND_IO_ERROR
 146 #define DRBD_ON_CONGESTION_DEF OC_BLOCK
 147
 148 #define DRBD_MAX_BIO_BVECS_MIN 0
 149 #define DRBD_MAX_BIO_BVECS_MAX 128
 150 #define DRBD_MAX_BIO_BVECS_DEF 0
 151
 152 #define DRBD_C_PLAN_AHEAD_MIN  0
 153 #define DRBD_C_PLAN_AHEAD_MAX  300
 154 #define DRBD_C_PLAN_AHEAD_DEF  0 /* RS rate controller disabled by default */
 155
 156 #define DRBD_C_DELAY_TARGET_MIN 1
 157 #define DRBD_C_DELAY_TARGET_MAX 100
 158 #define DRBD_C_DELAY_TARGET_DEF 10
 159
 160 #define DRBD_C_FILL_TARGET_MIN 0
 161 #define DRBD_C_FILL_TARGET_MAX (1<<20) /* 500MByte in sec */
 162 #define DRBD_C_FILL_TARGET_DEF 0 /* By default disabled -> controlled by delay_target */
 163
 164 #define DRBD_C_MAX_RATE_MIN     250 /* kByte/sec */
 165 #define DRBD_C_MAX_RATE_MAX     (4 << 20)
 166 #define DRBD_C_MAX_RATE_DEF     102400
 167
 168 #define DRBD_C_MIN_RATE_MIN     0 /* kByte/sec */
 169 #define DRBD_C_MIN_RATE_MAX     (4 << 20)
 170 #define DRBD_C_MIN_RATE_DEF     4096
 171
 172 #define DRBD_CONG_FILL_MIN      0
 173 #define DRBD_CONG_FILL_MAX      (10<<21) /* 10GByte in sectors */
 174 #define DRBD_CONG_FILL_DEF      0
 175
 176 #define DRBD_CONG_EXTENTS_MIN   DRBD_AL_EXTENTS_MIN
 177 #define DRBD_CONG_EXTENTS_MAX   DRBD_AL_EXTENTS_MAX
 178 #define DRBD_CONG_EXTENTS_DEF   DRBD_AL_EXTENTS_DEF
 179
 180 #define DRBD_PROTOCOL_DEF DRBD_PROT_C
 181
 182 #define DRBD_DISK_BARRIER_DEF   0
 183 #define DRBD_DISK_FLUSHES_DEF   1
 184 #define DRBD_DISK_DRAIN_DEF     1
 185 #define DRBD_MD_FLUSHES_DEF     1
 186 #define DRBD_TCP_CORK_DEF       1
 187
 188 #define DRBD_ALLOW_TWO_PRIMARIES_DEF    0
 189 #define DRBD_ALWAYS_ASBP_DEF    0
 190 #define DRBD_USE_RLE_DEF        0
 191
 192 #endif