1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
|
# Information about lizardfs, and some usage suggestions
On the octopus cluster the lizardfs head node is on octopus01, with disks being added mainly from the other nodes. SSDs are added to the lizardfs-chunkserver.service systemd service and SDDs added to the lizardfs-chunkserver-hdd.service. The storage pool is available on all nodes at /lizardfs, with the default storage option of "slow", which corresponds to two copies of the data, both on SDDs.
## Interacting with lizardfs
It is possible to query the server for all the available goals:
```
$ lizardfs-admin list-goals octopus01 9421
Goal definitions:
Id Name Definition
1 1_copy 1_copy: $std _
2 2_copy 2_copy: $std {_ _}
...
19 slow slow: $std {HDD HDD}
20 fast fast: $std {SSD SSD}
21 2ssd 2ssd: $std {SSD SSD}
...
```
To change the replication level:
```
$ lizardfs setgoal slow /lizardfs/efraimf -r
/lizardfs/efraimf/:
inodes with goal changed: 2
inodes with goal not changed: 0
inodes with permission denied: 0
```
And to see the replication level:
```
$ lizardfs getgoal /lizardfs/efraimf/
/lizardfs/efraimf/: slow
$ lizardfs getgoal /lizardfs/efraimf/ -r
/lizardfs/efraimf/:
files with goal slow : 1
directories with goal slow : 1
```
## Checking the health of the pool
There are a couple of commands which can be used to check on the health of the pool. They all take the syntax of `lizardfs-admin <command> <head-node> <port>`.
To find out the overall health of the data on the pool:
```
$ lizardfs-admin chunks-health octopus01 9421
Chunks availability state:
Goal Safe Unsafe Lost
slow 202726 26005 2073
fast 43397 1085 -
2ssd 7984 - -
Chunks replication state:
Goal 0 1 2 3 4 5 6 7 8 9 10+
slow 95 1870 228839 - - - - - - - -
fast 17253 2317 24912 - - - - - - - -
2ssd 7984 - - - - - - - - - -
Chunks deletion state:
Goal 0 1 2 3 4 5 6 7 8 9 10+
slow 68 15 2081 27598 201022 20 - - - - -
fast 12603 720 1880 5377 23902 - - - - - -
2ssd 7984 - - - - - - - - - -
```
To query how the individual disks are filling up and if there are any errors:
List all disks
```
lizardfs-admin list-disks octopus01 9421 | less
```
Other commands can be found with `man lizardfs-admin`.
## Deleted files
Lizardfs also keeps deleted files, by default for 30 days. If you need to recover deleted files (or delete them permanently) then the metadata directory can be mounted with:
```
$ mfsmount /path/to/unused/mount -o mfsmeta
```
For more information see the lizardfs documentation online
=> https://dev.lizardfs.com/docs/adminguide/advanced_configuration.html#trash-directory lizardfs documentation for the trash directory
## Gotchas
It should be noted that any goal using erasure_coding is incredibly slow to write to, and defining goals like this should be avoided. Although it does decrease the amount of space each file takes up in the pool, the trade-off when it is mistakenly used for data or folders which will be written to outweighs the benefits.
"speeding up" replication or resilvering of the data can be done in /etc/lizardfs/mfsmaster.cfg. Uncomment the following lines to increase their effect 10-fold from their defaults:
```
# CHUNKS_SOFT_DEL_LIMIT = 100
# CHUNKS_HARD_DEL_LIMIT = 250
# CHUNKS_WRITE_REP_LIMIT = 20
# CHUNKS_READ_REP_LIMIT = 100
```
followed by either restarting the lizardfs-master.service or by running (probably as root on octopus01):
```
lizardfs-admin reload-config octopus01 9421
```
It has not yet been tested to see how much this affects reading and writing to the HDDs or SSDs while this change is in effect.
# Adding a node to the pool
We can add a mount point using mfsmount using systemd
```
[Unit]
Description=LizardFS mounts
After=syslog.target network.target
[Service]
Type=forking
TimeoutSec=600
ExecStart=/usr/local/guix-profiles/octo/bin/mfsmount -c /etc/lizardfs/mfsmount.cfg
ExecStop=/usr/bin/umount /lizardfs
[Install]
WantedBy=multi-user.target
```
note it runs as the root user.
It is a good idea to also run a chunk server on the node, so it effectively can cache information locally. For this we create a lizard account:
```
addgroup -gid 600 lizardfs
adduser -uid 600 -gid 600 lizardfs
```
In password file
```
lizardfs:x:600:600:Lizard,,,:/var/lib/lizardfs:/bin/sbin/nologin
```
Now we can run
```
/usr/local/guix-profiles/octo/sbin/mfschunkserver -c /etc/lizardfs/mfschunkserver_hdd.cfg -d start
```
and set up systemd with something like
```
[Unit]
Description=LizardFS chunkserver daemon
Documentation=man:mfschunkserver
After=local-fs.target network.target lizardfs-master.service
Wants=local-fs.target network-online.target
[Service]
Type=notify
ExecStart=/usr/local/guix-profiles/octo/sbin/mfschunkserver -c /etc/lizardfs/mfschunkserver_hdd.cfg -d start
ExecReload=/bin/kill -HUP $MAINPID
Restart=on-abort
OOMScoreAdjust=-999
IOAccounting=true
IOWeight=250
StartupIOWeight=100
KeyringMode=inherit
[Install]
WantedBy=multi-user.target
```
|
