卷快照自动删除

适用于

• 产品型号： FAS3140-R5
• 操作系统： Data ONTAP 8.1.2 P2 7- 模式

问题

即使当前将 Snapshot 保留设置为 30 天、卷快照仍会自动删除。
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Snapshot autodelete settings for AUHVSNA1_SHARED:
                                        state=on
                                        commitment=try
                                        trigger=snap_reserve
                                        target_free_space=10%
                                        delete_order=oldest_first
                                        defer_delete=user_created
                                        prefix=(not specified)
                                        destroy_list=none =========================================
00000011.0010da6a 1b4cc5ac Tue Nov 25 2014 00:56:12  11:00 [wafl.volume.snap.autoDelete:info] Deleting snapshot 'weekly.0' in volume 'AUHVSNA1_SHARED' to recover storage
00000011.0010da6c 1b4cc63c Tue Nov 25 2014 00:56:27  11:00 [wafl.volume.snap.autoDelete:info] Deleting snapshot 'hourly.4' in volume 'AUHVSNA1_SHARED' to recover storage
00000011.0010da6e 1b4cc6d1 Tue Nov 25 2014 00:56:42  11:00 [wafl.volume.snap.autoDelete:info] Deleting snapshot 'hourly.3' in volume 'AUHVSNA1_SHARED' to recover storage
00000011.0010da70 1b4cc758 Tue Nov 25 2014 00:56:55  11:00 [wafl.volume.snap.autoDelete:info] Deleting snapshot 'hourly.1' in volume 'AUHVSNA1_SHARED' to recover storage
00000011.0010da72 1b4cc7f1 Tue Nov 25 2014 00:57:11  11:00 [wafl.volume.snap.autoDelete:info] Deleting snapshot 'hourly.0' in volume 'AUHVSNA1_SHARED' to recover storage
00000011.0010da74 1b4cc888 Tue Nov 25 2014 00:57:26  11:00 [wafl.volume.snap.autoDelete:info] Deleting snapshot 'nightly.0' in volume 'AUHVSNA1_SHARED' to recover storage
00000011.0010da76 1b4cc937 Tue Nov 25 2014 00:57:43  11:00 [wafl.volume.snap.autoDelete:info] Deleting snapshot 'Dont_Delete_INC0752286' in volume 'AUHVSNA1_SHARED' to recover storage
00000011.0010da79 1b4cc9ab Tue Nov 25 2014 00:57:55  11:00 [disk.healthTrigger:warning] Disk 3a.42 received NHT health trigger (0x1 0xb 0x5d 0x5)
00000011.0010da7a 1b4cc9e9 Tue Nov 25 2014 00:58:01  11:00 [wafl.volume.snap.autoDelete:info] Deleting snapshot 'Snapshot_4:45_24_11_2014' in volume 'AUHVSNA1_SHARED' to recover storage
00000011.0010da7c 1b4ccaa3 Tue Nov 25 2014 00:58:20  11:00 [wafl.volume.snap.autoDelete:info] Deleting snapshot 'Manual_snapshot' in volume 'AUHVSNA1_SHARED' to recover storage

As you can see here, On Nov 23, the volume /vol/AUHVSNA1_SHARED/ was at 96% capacity.  Something happened between Nov 23, and Nov 25 that pushed that volume to its capacity and snapshots were deleted on Nov 25 to save the volume.

Filesystem                         kbytes           used              avail    capacity  Mounted on
Nov 23
/vol/AUHVSNA1_SHARED/                               5653468812                 5424660856                  228807956      96%  /vol/AUHVSNA1_SHARED/
/vol/AUHVSNA1_SHARED/.snapshot             115376912                    87988840                      27388072      76%  /vol/AUHVSNA1_SHARED/.snapshot

Nov 25
/vol/AUHVSNA1_SHARED/                              5858989708                 5452568432                  406421276      93%  /vol/AUHVSNA1_SHARED/
/vol/AUHVSNA1_SHARED/.snapshot             119571216                    2969476                         116601740       2%  /vol/AUHVSNA1_SHARED/.snapshot
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最早的快照是在指定选项时首先删除的、但为了保持卷的活动状态、由于空间问题、即卷容量为 96% 、空间用尽、快照会一直删除、直到空间足够为止。 

此时发生了将卷推入容量的情况、并且所有快照都已删除。如果允许卷空间，则删除进程将在一个快照处停止；但是，卷空间不允许。 

此外、target_free_space设置为 10% 、请参见 Deleting Snapshot Copies automaticy:

target_free_space 确定何时停止删除 Snapshot 副本。target_free_space该值是卷的某个百分比。例如，如果指定 20，则在可用空间达到卷的 20% 之前会一直删除 Snapshot 副本。

通常情况target_free_space下，指定的值比自动删除阈值少 2% 、以避免不必要地删除 Snapshot 副本。