Merge pull request loris-imageserver#157 from loris-imageserver/revise_cache_script

adds info about quota version or cache maintenance script

Author: jpstroop

bin/loris-cache_clean.sh

@@ -1,32 +1,36 @@
 #!/bin/bash
 
 #
-# cache_clean.sh
+# loris-cache_clean.sh
+#
 # Cron script for maintaining the loris cache size.
 #
 # CAUTION - This script deletes files. Be careful where you point it!
 #
-LOG="/var/log/loris/cache_clean.log"
 
-# Check that the cache directories...
+LOG="/var/log/loris2/cache_clean.log"
+
+# Check that the image cache directory...
 IMG_CACHE_DIR="/var/cache/loris/img"
-IMG_LINKS_DIR="/var/cache/loris/links"
 
-# ...is below a certain size...
+# ...is below a certain size and...
 REDUCE_TO=1048576 #1 gb
 # REDUCE_TO=1073741824 # 1 TB
 # REDUCE_TO=2147483648 # 2 TB
 
-# ...and when it is larger, start deleting files accessed more than a certain 
+# ...and when it is larger, start deleting files accessed more than a certain
 # number of days ago until the cache is smaller than the configured size.
 
-# Note the name of the variable __REDUCE_TO__: this should not be the total 
-# amount of space you can afford for the cache, but instead the total space 
-# you can afford MINUS the amount you expect the cache to grow in between 
+# Note the name of the variable __REDUCE_TO__: this should not be the total
+# amount of space you can afford for the cache, but instead the total space
+# you can afford MINUS the amount you expect the cache to grow in between
 # executions of this script.
 
 current_usage () {
-	du -sk $IMG_CACHE_DIR | cut -f 1
+	du -sk $IMG_CACHE_DIR | cut -f 1                     # Fine for a few GB...
+	# quota -Q -u loris | grep sdb1 | awk '{ print $2 }' # ...much faster!!
+	# Note that you'll like need to change the name of the filesystem above if
+	# using the `quota` version.
 }
 
 delete_total=0
@@ -43,9 +47,6 @@ while [ $usage -gt $REDUCE_TO ] && [ $max_age -ge -1 ]; do
 		let delete_total+=1
 	done
 
-	# broken symlinks
-	find -L $IMG_LINKS_DIR -type l -delete
-
 	# empty directories
 	find $IMG_CACHE_DIR -mindepth 1 -type d -empty -delete
 
@@ -60,7 +61,3 @@ if [ $run == 0 ]; then
 else
 	echo "Cache at $usage kb (no deletes required)." >> $LOG
 fi
-
-
-
-

doc/cache_maintenance.md

@@ -7,11 +7,11 @@ There are two a Bash scripts at `bin/loris-cache_clean.sh` and `bin/loris-http_c
 
 __`setup.py` will not move or deploy the script for you.__ You can do this with, e.g. `sudo crontab -e -u loris` (replace `loris` with a user that has permission to delete files from the cache).
 
-`du` can take a very long time to run if you've configured your cache to be very large. In this case, consider setting an arbitrarily high disk usage quota for the cache owner ('arbitrarily high' so that you don't get errors if you go over a bit between executions of the cron script), and replace the `current_usage()` function in the cron script with:
+`du` can take a very long time to run if you've configured your cache to be very large. In this case, consider setting an arbitrarily high disk usage quota for the cache owner ('arbitrarily high' so that you don't get errors if you go over a bit between executions of the cron script), and replace the `current_usage()` function in the cron script with something like (you'll probably have to adjust the name of the file system):
 
 ```bash
 current_usage () {
-	quota -Q -u loris |grep sdc1 | awk '{ print $2 }'
+	quota -Q -u loris | grep sdb1 | awk '{ print $2 }'
 }
 ```