I created a mapped device with a table consisting 10, 20 and 30 mirror targets to examine the memory consumption. You can see that the memory consumption is very high (in terms of mega). I also verified that CONFIG_BLK_DEV_INTEGRITY is disabled. Do you have any idea why does a mirror target consumes so much memory? For 10 mirror targets the memory consumption is ~7M: ========================================== [root@vpc09 ~]# free –m total used free shared buffers cached Mem: 7837 566 7271 0 105 372 -/+ buffers/cache: 88 7749 Swap: 0 0 0 [root@vpc09 ~]# dmsetup create mirror_dev /tmp/mirror_core_sync_10.txt [root@vpc09 ~]# free -m total used free shared buffers cached Mem: 7837 573 7264 0 105 372 -/+ buffers/cache: 95 7742 Swap: 0 0 0 For 20 mirror targets the memory consumption is ~12M: =========================================== [root@vpc09 ~]# dmsetup remove mirror_dev [root@vpc09 ~]# free –m total used free shared buffers cached Mem: 7837 566 7271 0 105 372 -/+ buffers/cache: 89 7749 Swap: 0 0 0 [root@vpc09 ~]# dmsetup create mirror_dev /tmp/mirror_core_sync_20.txt [root@vpc09 ~]# free –m total used free shared buffers cached Mem: 7837 580 7257 0 106 372 -/+ buffers/cache: 101 7736 Swap: 0 0 0 For 30 mirror targets the memory consumption is ~19M: =========================================== [root@vpc09 ~]# dmsetup remove mirror_dev [root@vpc09 ~]# free –m total used free shared buffers cached Mem: 7837 568 7269 0 106 372 -/+ buffers/cache: 89 7748 Swap: 0 0 0 [root@vpc09 ~]# dmsetup create mirror_dev /tmp/mirror_core_sync_30.txt [root@vpc09 ~]# free –m total used free shared buffers cached Mem: 7837 587 7250 0 106 372 -/+ buffers/cache: 108 7729 Swap: 0 0 0 This is how the mapped file table looks like (you get the picture for the other 20 and 30 target files): ============================================================================ [root@vpc09 ~]# cat /tmp/mirror_core_sync_10.txt 0 8 mirror core 2 8 sync 2 /dev/loop0 0 /dev/loop1 0 8 8 mirror core 2 8 sync 2 /dev/loop0 0 /dev/loop1 0 16 8 mirror core 2 8 sync 2 /dev/loop0 0 /dev/loop1 0 24 8 mirror core 2 8 sync 2 /dev/loop0 0 /dev/loop1 0 32 8 mirror core 2 8 sync 2 /dev/loop0 0 /dev/loop1 0 40 8 mirror core 2 8 sync 2 /dev/loop0 0 /dev/loop1 0 48 8 mirror core 2 8 sync 2 /dev/loop0 0 /dev/loop1 0 56 8 mirror core 2 8 sync 2 /dev/loop0 0 /dev/loop1 0 64 8 mirror core 2 8 sync 2 /dev/loop0 0 /dev/loop1 0 72 8 mirror core 2 8 sync 2 /dev/loop0 0 /dev/loop1 0 |
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