[Varnish] #219: Overflow when calculating remaining disk space on big disk (32 bits server)

Varnish varnish-bugs at projects.linpro.no
Wed Mar 12 23:02:28 CET 2008

#219: Overflow when calculating remaining disk space on big disk (32 bits server)
 Reporter:  pcarrier  |       Owner:  phk                                 
     Type:  defect    |      Status:  new                                 
 Priority:  normal    |   Milestone:                                      
Component:  varnishd  |     Version:  trunk                               
 Severity:  normal    |    Keywords:  overflow ondisk disk space remaining
 Varnishd seem to exhibite some kind of an overflow when calculating
 remaining disk space at startup.  More precisely, when it create the on
 disk cache file.

  # '''df''' [[BR]]
  Filesystem           1K-blocks      Used Available Use% Mounted on[[BR]]
  /dev/sda1            238656420  29305924 197227448  13% / [[BR]]
  # '''df -h'''[[BR]]
  Filesystem            Size  Used Avail Use% Mounted on[[BR]]
  /dev/sda1             228G   28G  189G  13%[[BR]]
  # ''' varnishd -f /etc/varnish/minimum.vcl -s
 file,/var/lib/varnish/varnish_cache_file,256M''' [[BR]]
  WARNING: storage file size reduced to 77925580 (80% of available disk
 space)file /var/lib/varnish/varnish_cache_file size 77922304 bytes (19053
 fs-blocks, 19053 pages)[[BR]]

 Strong indicator of the overflow theory:

  # '''dd if=/dev/zero of=/test bs=1M count=1500'''[[BR]]
  # '''rm /var/lib/varnish/varnish_cache_file''' [[BR]]
  # '''varnishd -f /etc/varnish/minimum.vcl -s
 file,/var/lib/varnish/varnish_cache_file,256M''' [[BR]]
  file /var/lib/varnish/varnish_cache_file size 268435456 bytes (65536 fs-
 blocks, 65536 pages)
  Using old SHMFILE[[BR]]
  # '''df'''[[BR]]
  /dev/sda1            238656420  30843452 195689920  14% /[[BR]]

 Version used:  1.1.2, official release, compiled with defaults options on
 a 32 bits Debian 4.0 [[BR]]
 Reproducibles:  yes [[BR]]
 Step to reproduce:  start varnish with "-s file,/file.cache,256M" on a
 disk with 197227568 KB free with the cache file not already created[[BR]]
 Temporary fix: create your cache file with `dd`

Ticket URL: <http://varnish.projects.linpro.no/ticket/219>
Varnish <http://varnish.projects.linpro.no/>
The Varnish HTTP Accelerator

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