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--- cluster:150 [2016/09/16 14:30]
hmeij07 [The problem]
+++ cluster:150 [2016/11/29 19:36] (current)
hmeij07
@@ Line 2: / Line 2: @@
 **[[cluster:0|Back]]**
+==== Rsync Daemon/Rsnapshot ====
-==== The problem ====
+==== The Problem ====
 Trying to offload heavy read/write traffic from our file server. I also did a deep information dive to assess if we could afford enterprise level storage. That answer basically means a $42K layout at the low end and up to $70K for the high end. I've detailed the result here [[cluster:149|Enterprise Storage]], lots to be gained by doing that but implementing the **Short Term** plan first as detailed on that page.
@@ Line 48: / Line 49: @@
 </code>
-Back on source server, configure the ''/etc/rsnapshot.conf'' file, here are my settings
+Back on target server where snapshots will reside, configure the ''/etc/rsnapshot.conf'' file, here are my settings
 <code>
@@ Line 86: / Line 87: @@
   * onefs is important
   * link_dest is important
-  * the backup command points to my private IP of source server using the Infiniband network and then points to the module define in ''/etc/rsync.conf'' on source server
+  * the backup command points to my private IP of source server using the Infiniband network and then points to the module defined in ''/etc/rsync.conf'' on source server
 Start things up
@@ Line 92: / Line 93: @@
 <code>
-# on source
+# on target
-/usr/local/bin/rsnapshot daily &
+[root@cottontail ~]# /usr/local/bin/rsnapshot daily &
-# watch on target
+# on source
 [root@sharptail ~]# lsof -i:873
 COMMAND   PID USER   FD   TYPE    DEVICE SIZE/OFF NODE NAME
@@ Line 101: / Line 102: @@
 rsync   17814 root    5u  IPv6 261839488      0t0  TCP *:rsync (LISTEN)
 rsync   29717 root    6u  IPv4 261962741      0t0  TCP sharptail-ib0:rsync->cottontail-ib0:54069 (ESTABLISHED)
+# check what rsync is doing
 [root@sharptail ~]# strace -p 29717
 Process 29717 attached - interrupt to quit
@@ Line 110: / Line 114: @@
 lstat("/home/hemamy/data-analysis-for-fcc-lattice-tetra/fcc/data-analysis-for-7-b-spacer/NPs-same-mass/old-data/msd/msd-diff-temp/5.0nmNP/a115ave-msd-5.0nmNP-t-115-tetras.dat", {st_mode=S_IFREG|0644, st_size=8, ...}) = 0
 open("/home/hemamy/data-analysis-for-fcc-lattice-tetra/fcc/data-analysis-for-7-b-spacer/NPs-same-mass/old-data/msd/msd-diff-temp/5.0nmNP/a115ave-msd-5.0nmNP-t-115-tetras.dat", O_RDONLY) = 5
+CTRL-C
+</code>
+Suggest you debug with a small directory first, /home is 10TB in our case with 40+ million files.
+Then remount the user inaccessible area /mnt/home/.snapshots for user access on /snapshots
+<code>
+# /etc/exports content, then exportfs -ra
+/mnt/home/.snapshots       localhost.localdomain(sync,rw,no_all_squash,no_root_squash)
+# /etc/fstab content, then mount /snapshot/daily.0
+/dev/mapper/VG0-lvhomesnaps        /mnt/home/.snapshots     xfs    rw,tcp,intr,bg              0 0
+localhost:/mnt/home/.snapshots/daily.0 /snapshots/daily.0   nfs   ro   0 0
+# test
+[root@cottontail .snapshots]# touch /snapshots/daily.0/sharptail/home/hmeij/tmp/foo
+touch: cannot touch `/snapshots/daily.0/sharptail/home/hmeij/tmp/foo': Read-only file system
+</code>
+Finally, if you get this error, which is hardly informative, you've set num-tries to 0 like I did and fussed over it for some time. Set to 1 or leave uncommented.
+<code>
+-09-15T11:37:06] /usr/local/bin/rsnapshot daily: ERROR: /usr/bin/rsync returned 0.00390625 while processing rsync://sharptail-ib00::root/home/hmeij/python/
 </code>
 \\
 **[[cluster:0|Back]]**

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