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Posted to issues@trafficserver.apache.org by "Leif Hedstrom (JIRA)" <ji...@apache.org> on 2013/12/20 22:56:10 UTC

[jira] [Created] (TS-2447) Cache fails to load / initialize, seems stuck on directory entry cleanup

Leif Hedstrom created TS-2447:
---------------------------------

             Summary: Cache fails to load / initialize, seems stuck on directory entry cleanup
                 Key: TS-2447
                 URL: https://issues.apache.org/jira/browse/TS-2447
             Project: Traffic Server
          Issue Type: Bug
          Components: Cache
            Reporter: Leif Hedstrom


We had an issue where a number of machines would not startup properly. They get stuck on reading / initializing the cache. It initializes the caches with

{code}
[Dec 20 16:45:40.195] Server {0x7f3f2f4ef7e0} DEBUG: (cache_hosting) Disk: 0: Vol Blocks: 1: Free space: 0
[Dec 20 16:45:40.195] Server {0x7f3f2f4ef7e0} DEBUG: (cache_hosting)    Vol: 0 Size: 62509342
[Dec 20 16:45:40.195] Server {0x7f3f2f4ef7e0} DEBUG: (cache_hosting)    Block No: 0 Size: 62509342 Free: 0
[Dec 20 16:45:40.195] Server {0x7f3f2f4ef7e0} DEBUG: (cache_hosting) Disk: 1: Vol Blocks: 1: Free space: 0
[Dec 20 16:45:40.195] Server {0x7f3f2f4ef7e0} DEBUG: (cache_hosting)    Vol: 0 Size: 62509342
[Dec 20 16:45:40.195] Server {0x7f3f2f4ef7e0} DEBUG: (cache_hosting)    Block No: 0 Size: 62509342 Free: 0
[Dec 20 16:45:40.195] Server {0x7f3f2f4ef7e0} DEBUG: (cache_hosting) Disk: 2: Vol Blocks: 1: Free space: 0
[Dec 20 16:45:40.195] Server {0x7f3f2f4ef7e0} DEBUG: (cache_hosting)    Vol: 0 Size: 62509342
[Dec 20 16:45:40.195] Server {0x7f3f2f4ef7e0} DEBUG: (cache_hosting)    Block No: 0 Size: 62509342 Free: 0
[Dec 20 16:45:40.195] Server {0x7f3f2f4ef7e0} DEBUG: (cache_hosting) Disk: 3: Vol Blocks: 1: Free space: 0
[Dec 20 16:45:40.195] Server {0x7f3f2f4ef7e0} DEBUG: (cache_hosting)    Vol: 0 Size: 62509342
[Dec 20 16:45:40.195] Server {0x7f3f2f4ef7e0} DEBUG: (cache_hosting)    Block No: 0 Size: 62509342 Free: 0
[Dec 20 16:45:40.195] Server {0x7f3f2f4ef7e0} DEBUG: (cache_hosting) Disk: 4: Vol Blocks: 1: Free space: 0
[Dec 20 16:45:40.195] Server {0x7f3f2f4ef7e0} DEBUG: (cache_hosting)    Vol: 0 Size: 62509342
[Dec 20 16:45:40.195] Server {0x7f3f2f4ef7e0} DEBUG: (cache_hosting)    Block No: 0 Size: 62509342 Free: 0
[Dec 20 16:45:40.195] Server {0x7f3f2f4ef7e0} DEBUG: (cache_hosting) Disk: 5: Vol Blocks: 1: Free space: 0
[Dec 20 16:45:40.195] Server {0x7f3f2f4ef7e0} DEBUG: (cache_hosting)    Vol: 0 Size: 62509342
[Dec 20 16:45:40.195] Server {0x7f3f2f4ef7e0} DEBUG: (cache_hosting)    Block No: 0 Size: 62509342 Free: 0
[Dec 20 16:45:40.195] Server {0x7f3f2f4ef7e0} DEBUG: (cache_hosting) Disk: 6: Vol Blocks: 1: Free space: 0
[Dec 20 16:45:40.195] Server {0x7f3f2f4ef7e0} DEBUG: (cache_hosting)    Vol: 0 Size: 62509342
[Dec 20 16:45:40.195] Server {0x7f3f2f4ef7e0} DEBUG: (cache_hosting)    Block No: 0 Size: 62509342 Free: 0
[Dec 20 16:45:40.195] Server {0x7f3f2f4ef7e0} DEBUG: (cache_init) Cache::open - proxy.config.cache.min_average_object_size = 65536
[Dec 20 16:45:40.198] Server {0x7f3f2f4ef7e0} DEBUG: (cache_init) allocating 78135296 directory bytes for a 512076529664 byte volume (0.015259%)
[Dec 20 16:45:40.201] Server {0x7f3f2f4ef7e0} DEBUG: (cache_init) allocating 78135296 directory bytes for a 512076529664 byte volume (0.015259%)
[Dec 20 16:45:40.204] Server {0x7f3f2f4ef7e0} DEBUG: (cache_init) allocating 78135296 directory bytes for a 512076529664 byte volume (0.015259%)
[Dec 20 16:45:40.208] Server {0x7f3f2f4ef7e0} DEBUG: (cache_init) allocating 78135296 directory bytes for a 512076529664 byte volume (0.015259%)
[Dec 20 16:45:40.213] Server {0x7f3f2f4ef7e0} DEBUG: (cache_init) allocating 78135296 directory bytes for a 512076529664 byte volume (0.015259%)
[Dec 20 16:45:40.219] Server {0x7f3f2f4ef7e0} DEBUG: (cache_init) allocating 78135296 directory bytes for a 512076529664 byte volume (0.015259%)
[Dec 20 16:45:40.224] Server {0x7f3f2f4ef7e0} DEBUG: (cache_init) allocating 78135296 directory bytes for a 512076529664 byte volume (0.015259%)
{code}

After this, it enters a stage where it’s doing a *lot* of dir_clean events:

{code}
[Dec 20 16:45:40.314] Server {0x7f3f26f91700} DEBUG: (dir_clean) cleaning 0x7f3edcd6f028 tag 0 boffset 0 b 0x7f3edcd6f028 p (nil) l 1
[Dec 20 16:45:40.314] Server {0x7f3f26f91700} DEBUG: (dir_clean) cleaning 0x7f3edcd6f050 tag 0 boffset 0 b 0x7f3edcd6f050 p (nil) l 1
[Dec 20 16:45:40.314] Server {0x7f3f26f91700} DEBUG: (dir_clean) cleaning 0x7f3edcd6f078 tag 0 boffset 0 b 0x7f3edcd6f078 p (nil) l 1
[Dec 20 16:45:40.314] Server {0x7f3f26f91700} DEBUG: (dir_clean) cleaning 0x7f3edcd6f0a0 tag 0 boffset 0 b 0x7f3edcd6f0a0 p (nil) l 1
[Dec 20 16:45:40.314] Server {0x7f3f26f91700} DEBUG: (dir_clean) cleaning 0x7f3edcd6f0c8 tag 0 boffset 0 b 0x7f3edcd6f0c8 p (nil) l 1
[Dec 20 16:45:40.314] Server {0x7f3f26f91700} DEBUG: (dir_clean) cleaning 0x7f3edcd6f0f0 tag 0 boffset 0 b 0x7f3edcd6f0f0 p (nil) l 1
[Dec 20 16:45:40.314] Server {0x7f3f26f91700} DEBUG: (dir_clean) cleaning 0x7f3edcd6f140 tag 0 boffset 0 b 0x7f3edcd6f140 p (nil) l 1
{code}

This goes on for a while, until it reaches some state where one entry is cyclical, interspersed with other entries:

{code}
[Dec 20 16:45:51.651] Server {0x7f3f282a4700} DEBUG: (dir_clean) cleaning 0x7f3eeb78c3f0 tag 2A7 boffset 0 b 0x7f3eeb78c3f0 p (nil) l -1
[Dec 20 16:45:51.651] Server {0x7f3f27d9f700} DEBUG: (dir_clean) cleaning 0x7f3ece462c98 tag 0 boffset 0 b 0x7f3ece462c98 p (nil) l 1
[Dec 20 16:45:51.651] Server {0x7f3f285a7700} DEBUG: (dir_clean) cleaning 0x7f3ed81d22b0 tag 0 boffset 0 b 0x7f3ed81d22b0 p (nil) l 1
[Dec 20 16:45:51.651] Server {0x7f3f2f4ef7e0} DEBUG: (dir_clean) cleaning 0x7f3ed32fb2a0 tag 0 boffset 0 b 0x7f3ed32fb2a0 p (nil) l 1
[Dec 20 16:45:51.651] Server {0x7f3f27ea0700} DEBUG: (dir_clean) cleaning 0x7f3ee1f66060 tag 0 boffset 0 b 0x7f3ee1f66060 p (nil) l 1
[Dec 20 16:45:51.651] Server {0x7f3f26f91700} DEBUG: (dir_clean) cleaning 0x7f3edd093420 tag 0 boffset 0 b 0x7f3edd093420 p (nil) l 1
[Dec 20 16:45:51.651] Server {0x7f3f280a2700} DEBUG: (dir_clean) cleaning 0x7f3ee6e0ea18 tag 0 boffset 0 b 0x7f3ee6e0ea18 p (nil) l 1
[Dec 20 16:45:51.651] Server {0x7f3f282a4700} DEBUG: (dir_clean) cleaning 0x7f3eeb78c3f0 tag C0 boffset 0 b 0x7f3eeb78c3f0 p (nil) l -1
[Dec 20 16:45:51.651] Server {0x7f3f27d9f700} DEBUG: (dir_clean) cleaning 0x7f3ece462ce8 tag 0 boffset 0 b 0x7f3ece462ce8 p (nil) l 1
[Dec 20 16:45:51.651] Server {0x7f3f285a7700} DEBUG: (dir_clean) cleaning 0x7f3ed81d22d8 tag 0 boffset 0 b 0x7f3ed81d22d8 p (nil) l 1
[Dec 20 16:45:51.651] Server {0x7f3f2f4ef7e0} DEBUG: (dir_clean) cleaning 0x7f3ed32fb2f0 tag 0 boffset 0 b 0x7f3ed32fb2f0 p (nil) l 1
[Dec 20 16:45:51.651] Server {0x7f3f27ea0700} DEBUG: (dir_clean) cleaning 0x7f3ee1f660b0 tag 0 boffset 0 b 0x7f3ee1f660b0 p (nil) l 1
{code}

Note how 0x7f3eeb78c3f0 is repeated once in a while. After this goes on for quite a while, it ends up in a state like this:

{code}
[Dec 20 17:02:28.914] Server {0x7f3f282a4700} DEBUG: (dir_clean) cleaning 0x7f3eeb78c3f0 tag FFE boffset 0 b 0x7f3eeb78c3f0 p (nil) l -1
[Dec 20 17:02:28.914] Server {0x7f3f282a4700} DEBUG: (dir_clean) cleaning 0x7f3eeb78c3f0 tag FFA boffset 0 b 0x7f3eeb78c3f0 p (nil) l -1
[Dec 20 17:02:28.914] Server {0x7f3f282a4700} DEBUG: (dir_clean) cleaning 0x7f3eeb78c3f0 tag FF6 boffset 0 b 0x7f3eeb78c3f0 p (nil) l -1
[Dec 20 17:02:28.914] Server {0x7f3f282a4700} DEBUG: (dir_clean) cleaning 0x7f3eeb78c3f0 tag FF2 boffset 0 b 0x7f3eeb78c3f0 p (nil) l -1
[Dec 20 17:02:28.914] Server {0x7f3f282a4700} DEBUG: (dir_clean) cleaning 0x7f3eeb78c3f0 tag FEE boffset 0 b 0x7f3eeb78c3f0 p (nil) l -1
[Dec 20 17:02:28.914] Server {0x7f3f282a4700} DEBUG: (dir_clean) cleaning 0x7f3eeb78c3f0 tag FEA boffset 0 b 0x7f3eeb78c3f0 p (nil) l -1
.
.
.
[Dec 20 17:02:28.922] Server {0x7f3f282a4700} DEBUG: (dir_clean) cleaning 0x7f3eeb78c3f0 tag 16 boffset 0 b 0x7f3eeb78c3f0 p(nil) l -1
[Dec 20 17:02:28.922] Server {0x7f3f282a4700} DEBUG: (dir_clean) cleaning 0x7f3eeb78c3f0 tag 12 boffset 0 b 0x7f3eeb78c3f0 p(nil) l -1
[Dec 20 17:02:28.922] Server {0x7f3f282a4700} DEBUG: (dir_clean) cleaning 0x7f3eeb78c3f0 tag E boffset 0 b 0x7f3eeb78c3f0 p (nil) l -1
[Dec 20 17:02:28.922] Server {0x7f3f282a4700} DEBUG: (dir_clean) cleaning 0x7f3eeb78c3f0 tag A boffset 0 b 0x7f3eeb78c3f0 p (nil) l -1
[Dec 20 17:02:28.922] Server {0x7f3f282a4700} DEBUG: (dir_clean) cleaning 0x7f3eeb78c3f0 tag 6 boffset 0 b 0x7f3eeb78c3f0 p (nil) l -1
[Dec 20 17:02:28.922] Server {0x7f3f282a4700} DEBUG: (dir_clean) cleaning 0x7f3eeb78c3f0 tag 2 boffset 0 b 0x7f3eeb78c3f0 p (nil) l -1
[Dec 20 17:02:28.922] Server {0x7f3f282a4700} DEBUG: (dir_clean) cleaning 0x7f3eeb78c3f0 tag FFE boffset 0 b 0x7f3eeb78c3f0 p (nil) l -1
[Dec 20 17:02:28.922] Server {0x7f3f282a4700} DEBUG: (dir_clean) cleaning 0x7f3eeb78c3f0 tag FFA boffset 0 b 0x7f3eeb78c3f0 p (nil) l -1
.
.
.
{code}

This last state never finishes, it seems to loop through the tag’s repeatedly forever. It consumes 100% of one CPU while doing this. I have no idea what this actually means yet, other than the debug tag comes from a test where we verify 

{code}
   if (!dir_valid(vol, e) || !dir_offset(e)) {
{code}

I don’t know if this is a regression, a new bug, or something we’ve always had. In all my years running at Yahoo, we never ran into this, and we’ve now run into this 3-4 times at least in a short time here. I think I had it happen in my lab box once, unfortunately I didn’t recognize it as such, and cleared the cache.It happened once while debugging something else, and I was restarting ATS frequently.

Oh yeah, doing a “traffic_server -Cclear” obviously fixes the broken cache.




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