translators and their subvolumes? ("dangling volume. check volfile")

[mangoo at wpkg.org (Tomasz Chmielewski)]

Which is the correct way to configure translators? Should they all point 
to one other volume (i.e. readahead, writebehind, io-cache, quick-read, 
stat-prefetch should all have a "subvolumes replicate1" entry)?

Or rather, all subsequent volumes should point at each other?


1. Variant one - all point to "replicate1":

volume remote1
   type protocol/client
   option transport-type tcp
   option remote-host alpha-int
   option remote-subvolume brick
end-volume

volume remote2
   type protocol/client
   option transport-type tcp
   option remote-host omega-int
   option remote-subvolume brick
end-volume

volume replicate1
   type cluster/replicate
   option read-subvolume remote2
   subvolumes remote1 remote2
end-volume

volume readahead
   type performance/read-ahead
   option page-count 16           # 2 is default option
   option force-atime-update off # default is off
   subvolumes replicate1
end-volume

volume writebehind
   type performance/write-behind
   option cache-size 128MB    # default is equal to aggregate-size
   option flush-behind on    # default is 'off'
   subvolumes replicate1
end-volume

volume io-cache
   type performance/io-cache
   option cache-size 1024MB             # default is 32MB
   option cache-timeout 4             # default is 1 second
   subvolumes replicate1
end-volume

volume quick-read
   type performance/quick-read
   option cache-timeout 4
   option max-file-size 1024000
   subvolumes replicate1
end-volume

volume stat-prefetch
   type performance/stat-prefetch
   subvolumes replicate1
end-volume



2. Variant two - volumes point at each other (stat-prefetch -> 
quick-read -> io-cache -> writebehind -> readahead -> replicate1).

volume remote1
   type protocol/client
   option transport-type tcp
   option remote-host alpha-int
   option remote-subvolume brick
end-volume

volume remote2
   type protocol/client
   option transport-type tcp
   option remote-host omega-int
   option remote-subvolume brick
end-volume

volume replicate1
   type cluster/replicate
   option read-subvolume remote2
#  option favorite-child remote1
   subvolumes remote1 remote2
end-volume

volume readahead
   type performance/read-ahead
   option page-count 16           # 2 is default option
   option force-atime-update off # default is off
   subvolumes replicate1
end-volume

volume writebehind
   type performance/write-behind
   option cache-size 128MB    # default is equal to aggregate-size
   option flush-behind on    # default is 'off'
   subvolumes readahead
end-volume

volume io-cache
   type performance/io-cache
   option cache-size 1024MB             # default is 32MB
   option cache-timeout 4             # default is 1 second
   subvolumes writebehind
end-volume

volume quick-read
   type performance/quick-read
   option cache-timeout 4
   option max-file-size 1024000
   subvolumes io-cache
end-volume

volume stat-prefetch
   type performance/stat-prefetch
   subvolumes quick-read
end-volume


-- 
Tomasz Chmielewski
http://wpkg.org