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[英]ceph raw used is more than sum of used in all pools (ceph df detail)
[英]ceph df (octopus) shows USED is 7 times higher than STORED in erasure coded pool
池default.rgw.buckets.data已存儲501 GiB ,但 USED 顯示3.5 TiB 。
root@ceph-01:~# ceph df
--- RAW STORAGE ---
CLASS SIZE AVAIL USED RAW USED %RAW USED
hdd 196 TiB 193 TiB 3.5 TiB 3.6 TiB 1.85
TOTAL 196 TiB 193 TiB 3.5 TiB 3.6 TiB 1.85
--- POOLS ---
POOL ID PGS STORED OBJECTS USED %USED MAX AVAIL
device_health_metrics 1 1 19 KiB 12 56 KiB 0 61 TiB
.rgw.root 2 32 2.6 KiB 6 1.1 MiB 0 61 TiB
default.rgw.log 3 32 168 KiB 210 13 MiB 0 61 TiB
default.rgw.control 4 32 0 B 8 0 B 0 61 TiB
default.rgw.meta 5 8 4.8 KiB 11 1.9 MiB 0 61 TiB
default.rgw.buckets.index 6 8 1.6 GiB 211 4.7 GiB 0 61 TiB
default.rgw.buckets.data 10 128 501 GiB 5.36M 3.5 TiB 1.90 110 TiB
default.rgw.buckets.data池使用糾刪碼:
root@ceph-01:~# ceph osd erasure-code-profile get EC_RGW_HOST
crush-device-class=hdd
crush-failure-domain=host
crush-root=default
jerasure-per-chunk-alignment=false
k=6
m=4
plugin=jerasure
technique=reed_sol_van
w=8
如果有人可以幫助解釋為什么它使用了 7 倍以上的空間,那將有很大幫助。 版本控制被禁用。 ceph 版本 15.2.13(章魚穩定)。
這與 bluestore_min_alloc_size_hdd=64K(八達通的默認值)有關。
如果使用擦除編碼,數據會被分成更小的塊,每個塊在磁盤上占用 64K。
一種選擇是將 bluestore_min_alloc_size_hdd 降低到 4K,如果您的解決方案需要存儲數百萬個微小 (16K) 對象,這很好。 就我而言,我存儲了數億張 3-4M 的照片,所以我決定跳過擦除編碼,繼續使用 bluestore_min_alloc_size_hdd=64K 並切換到復制 3(最少 2)。 從長遠來看,這更安全、更快。
以下是 Josh Baergen 在郵件列表中的回復:
Hey Arkadiy,
If the OSDs are on HDDs and were created with the default
bluestore_min_alloc_size_hdd, which is still 64KiB in Octopus, then in
effect data will be allocated from the pool in 640KiB chunks (64KiB *
(k+m)). 5.36M objects taking up 501GiB is an average object size of 98KiB
which results in a ratio of 6.53:1 allocated:stored, which is pretty close
to the 7:1 observed.
If my assumption about your configuration is correct, then the only way to
fix this is to adjust bluestore_min_alloc_size_hdd and recreate all your
OSDs, which will take a while...
Josh
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