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    Hi all,<br>
    Ive been testing Varnish over the past while and have a few
    questions with which i hope you can help.<br>
    We have deployed Varnish 3.0.2 in front of our XML api.<br>
    During my load testing Ive noticed that the session_linger and
    session_herd stats are quite high. Does this signal an issue?<br>
    <br>
    Also, during my load testing Im getting an error for 0.04% of
    requests to Varnish - "readResponse: java.net.SocketException:
    Connection reset ". Has anyone seen this before? Are these
    connections getting closed on the Varnish side?<br>
    I had been using the default setting for session_linger but changed
    it to 0. Do I need session linger considering I am not caching a web
    page but am instead caching XML api responses?<br>
    <br>
    I was surprised how little memory Varnish is using to cache its
    objects - this is reflect in the line <br>
    <small>SMA.s0.g_bytes           2109235          .   Bytes
      outstanding</small><br>
    <br>
    The following are the output from varnishstat -1 and also the
    param.show. The VCL in play is very simple and passes through 1
    request type and caches everything else.<br>
    Thanks for you help in advance,<br>
    Barry<br>
    <br>
    <small>client_conn            5990408        14.10 Client
      connections accepted<br>
      client_drop                  0         0.00 Connection dropped, no
      sess/wrk<br>
      client_req          2351555655      5534.53 Client requests
      received<br>
      cache_hit           2346417108      5522.44 Cache hits<br>
      cache_hitpass                0         0.00 Cache hits for pass<br>
      cache_miss             4836412        11.38 Cache misses<br>
      backend_conn             11271         0.03 Backend conn. success<br>
      backend_unhealthy            0         0.00 Backend conn. not
      attempted<br>
      backend_busy                 0         0.00 Backend conn. too many<br>
      backend_fail                 2         0.00 Backend conn. failures<br>
      backend_reuse          5127357        12.07 Backend conn. reuses<br>
      backend_toolate           1044         0.00 Backend conn. was
      closed<br>
      backend_recycle        5128407        12.07 Backend conn. recycles<br>
      backend_retry               99         0.00 Backend conn. retry<br>
      fetch_head              295036         0.69 Fetch head<br>
      fetch_length           4836477        11.38 Fetch with Length<br>
      fetch_chunked             7012         0.02 Fetch chunked<br>
      fetch_eof                    0         0.00 Fetch EOF<br>
      fetch_bad                    0         0.00 Fetch had bad headers<br>
      fetch_close                  0         0.00 Fetch wanted close<br>
      fetch_oldhttp                0         0.00 Fetch pre HTTP/1.1
      closed<br>
      fetch_zero                   0         0.00 Fetch zero len<br>
      fetch_failed                 0         0.00 Fetch failed<br>
      fetch_1xx                    0         0.00 Fetch no body (1xx)<br>
      fetch_204                    0         0.00 Fetch no body (204)<br>
      fetch_304                    0         0.00 Fetch no body (304)<br>
      n_sess_mem                1251          .   N struct sess_mem<br>
      n_sess                     789          .   N struct sess<br>
      n_object                   453          .   N struct object<br>
      n_vampireobject              0          .   N unresurrected
      objects<br>
      n_objectcore               627          .   N struct objectcore<br>
      n_objecthead              1859          .   N struct objecthead<br>
      n_waitinglist            15213          .   N struct waitinglist<br>
      n_vbc                        5          .   N struct vbc<br>
      n_wrk                      174          .   N worker threads<br>
      n_wrk_create             10484         0.02 N worker threads
      created<br>
      n_wrk_failed                 0         0.00 N worker threads not
      created<br>
      n_wrk_max                    0         0.00 N worker threads
      limited<br>
      n_wrk_lqueue                 0         0.00 work request queue
      length<br>
      n_wrk_queued            514194         1.21 N queued work requests<br>
      n_wrk_drop                   0         0.00 N dropped work
      requests<br>
      n_backend                    1          .   N backends<br>
      n_expired              4835952          .   N expired objects<br>
      n_lru_nuked                  0          .   N LRU nuked objects<br>
      n_lru_moved           33485426          .   N LRU moved objects<br>
      losthdr                      0         0.00 HTTP header overflows<br>
      n_objsendfile                0         0.00 Objects sent with
      sendfile<br>
      n_objwrite          2351109391      5533.48 Objects sent with
      write<br>
      n_objoverflow                0         0.00 Objects overflowing
      workspace<br>
      s_sess                 5990506        14.10 Total Sessions<br>
      s_req               2351555664      5534.53 Total Requests<br>
      s_pipe                       0         0.00 Total pipe<br>
      s_pass                  302120         0.71 Total pass<br>
      s_fetch                5138525        12.09 Total fetch<br>
      s_hdrbytes        544265355452   1280961.94 Total header bytes<br>
      s_bodybytes       3089476577758   7271272.85 Total body bytes<br>
      sess_closed             227804         0.54 Session Closed<br>
      sess_pipeline                0         0.00 Session Pipeline<br>
      sess_readahead               0         0.00 Session Read Ahead<br>
      sess_linger         2209279166      5199.67 Session Linger<br>
      sess_herd            323937467       762.41 Session herd<br>
      shm_records        89745845415    211222.36 SHM records<br>
      shm_writes          2562338698      6030.62 SHM writes<br>
      shm_flushes                 62         0.00 SHM flushes due to
      overflow<br>
      shm_cont              27674729        65.13 SHM MTX contention<br>
      shm_cycles               43605         0.10 SHM cycles through
      buffer<br>
      sms_nreq                    22         0.00 SMS allocator requests<br>
      sms_nobj                     0          .   SMS outstanding
      allocations<br>
      sms_nbytes                   0          .   SMS outstanding bytes<br>
      sms_balloc                8856          .   SMS bytes allocated<br>
      sms_bfree                 8856          .   SMS bytes freed<br>
      backend_req            5138625        12.09 Backend requests made<br>
      n_vcl                        1         0.00 N vcl total<br>
      n_vcl_avail                  1         0.00 N vcl available<br>
      n_vcl_discard                0         0.00 N vcl discarded<br>
      n_ban                        1          .   N total active bans<br>
      n_ban_add                    1         0.00 N new bans added<br>
      n_ban_retire                 0         0.00 N old bans deleted<br>
      n_ban_obj_test               0         0.00 N objects tested<br>
      n_ban_re_test                0         0.00 N regexps tested
      against<br>
      n_ban_dups                   0         0.00 N duplicate bans
      removed<br>
      hcb_nolock          2351224626      5533.75 HCB Lookups without
      lock<br>
      hcb_lock               1666108         3.92 HCB Lookups with lock<br>
      hcb_insert             1666107         3.92 HCB Inserts<br>
      esi_errors                   0         0.00 ESI parse errors
      (unlock)<br>
      esi_warnings                 0         0.00 ESI parse warnings
      (unlock)<br>
      accept_fail                  0         0.00 Accept failures<br>
      client_drop_late             0         0.00 Connection dropped
      late<br>
      uptime                  424888         1.00 Client uptime<br>
      dir_dns_lookups              0         0.00 DNS director lookups<br>
      dir_dns_failed               0         0.00 DNS director failed
      lookups<br>
      dir_dns_hit                  0         0.00 DNS director cached
      lookups hit<br>
      dir_dns_cache_full           0         0.00 DNS director full
      dnscache<br>
      vmods                        0          .   Loaded VMODs<br>
      n_gzip                       0         0.00 Gzip operations<br>
      n_gunzip            2355834985      5544.60 Gunzip operations<br>
      LCK.sms.creat                1         0.00 Created locks<br>
      LCK.sms.destroy              0         0.00 Destroyed locks<br>
      LCK.sms.locks               66         0.00 Lock Operations<br>
      LCK.sms.colls                0         0.00 Collisions<br>
      LCK.smp.creat                0         0.00 Created locks<br>
      LCK.smp.destroy              0         0.00 Destroyed locks<br>
      LCK.smp.locks                0         0.00 Lock Operations<br>
      LCK.smp.colls                0         0.00 Collisions<br>
      LCK.sma.creat                2         0.00 Created locks<br>
      LCK.sma.destroy              0         0.00 Destroyed locks<br>
      LCK.sma.locks         24799574        58.37 Lock Operations<br>
      LCK.sma.colls                0         0.00 Collisions<br>
      LCK.smf.creat                0         0.00 Created locks<br>
      LCK.smf.destroy              0         0.00 Destroyed locks<br>
      LCK.smf.locks                0         0.00 Lock Operations<br>
      LCK.smf.colls                0         0.00 Collisions<br>
      LCK.hsl.creat                0         0.00 Created locks<br>
      LCK.hsl.destroy              0         0.00 Destroyed locks<br>
      LCK.hsl.locks                0         0.00 Lock Operations<br>
      LCK.hsl.colls                0         0.00 Collisions<br>
      LCK.hcb.creat                1         0.00 Created locks<br>
      LCK.hcb.destroy              0         0.00 Destroyed locks<br>
      LCK.hcb.locks          3334164         7.85 Lock Operations<br>
      LCK.hcb.colls                0         0.00 Collisions<br>
      LCK.hcl.creat                0         0.00 Created locks<br>
      LCK.hcl.destroy              0         0.00 Destroyed locks<br>
      LCK.hcl.locks                0         0.00 Lock Operations<br>
      LCK.hcl.colls                0         0.00 Collisions<br>
      LCK.vcl.creat                1         0.00 Created locks<br>
      LCK.vcl.destroy              0         0.00 Destroyed locks<br>
      LCK.vcl.locks            32230         0.08 Lock Operations<br>
      LCK.vcl.colls                0         0.00 Collisions<br>
      LCK.stat.creat               1         0.00 Created locks<br>
      LCK.stat.destroy             0         0.00 Destroyed locks<br>
      LCK.stat.locks            1251         0.00 Lock Operations<br>
      LCK.stat.colls               0         0.00 Collisions<br>
      LCK.sessmem.creat            1         0.00 Created locks<br>
      LCK.sessmem.destroy            0         0.00 Destroyed locks<br>
      LCK.sessmem.locks        5999643        14.12 Lock Operations<br>
      LCK.sessmem.colls              0         0.00 Collisions<br>
      LCK.wstat.creat                1         0.00 Created locks<br>
      LCK.wstat.destroy              0         0.00 Destroyed locks<br>
      LCK.wstat.locks        155943114       367.02 Lock Operations<br>
      LCK.wstat.colls                0         0.00 Collisions<br>
      LCK.herder.creat               1         0.00 Created locks<br>
      LCK.herder.destroy             0         0.00 Destroyed locks<br>
      LCK.herder.locks           25245         0.06 Lock Operations<br>
      LCK.herder.colls               0         0.00 Collisions<br>
      LCK.wq.creat                   2         0.00 Created locks<br>
      LCK.wq.destroy                 0         0.00 Destroyed locks<br>
      LCK.wq.locks           649162540      1527.84 Lock Operations<br>
      LCK.wq.colls                   0         0.00 Collisions<br>
      LCK.objhdr.creat         1676572         3.95 Created locks<br>
      LCK.objhdr.destroy       1674713         3.94 Destroyed locks<br>
      LCK.objhdr.locks      9417295559     22164.18 Lock Operations<br>
      LCK.objhdr.colls               0         0.00 Collisions<br>
      LCK.exp.creat                  1         0.00 Created locks<br>
      LCK.exp.destroy                0         0.00 Destroyed locks<br>
      LCK.exp.locks           10095406        23.76 Lock Operations<br>
      LCK.exp.colls                  0         0.00 Collisions<br>
      LCK.lru.creat                  2         0.00 Created locks<br>
      LCK.lru.destroy                0         0.00 Destroyed locks<br>
      LCK.lru.locks            4836405        11.38 Lock Operations<br>
      LCK.lru.colls                  0         0.00 Collisions<br>
      LCK.cli.creat                  1         0.00 Created locks<br>
      LCK.cli.destroy                0         0.00 Destroyed locks<br>
      LCK.cli.locks             141594         0.33 Lock Operations<br>
      LCK.cli.colls                  0         0.00 Collisions<br>
      LCK.ban.creat                  1         0.00 Created locks<br>
      LCK.ban.destroy                0         0.00 Destroyed locks<br>
      LCK.ban.locks           10095484        23.76 Lock Operations<br>
      LCK.ban.colls                  0         0.00 Collisions<br>
      LCK.vbp.creat                  1         0.00 Created locks<br>
      LCK.vbp.destroy                0         0.00 Destroyed locks<br>
      LCK.vbp.locks                  0         0.00 Lock Operations<br>
      LCK.vbp.colls                  0         0.00 Collisions<br>
      LCK.vbe.creat                  1         0.00 Created locks<br>
      LCK.vbe.destroy                0         0.00 Destroyed locks<br>
      LCK.vbe.locks              22541         0.05 Lock Operations<br>
      LCK.vbe.colls                  0         0.00 Collisions<br>
      LCK.backend.creat              1         0.00 Created locks<br>
      LCK.backend.destroy            0         0.00 Destroyed locks<br>
      LCK.backend.locks       13459516        31.68 Lock Operations<br>
      LCK.backend.colls              0         0.00 Collisions<br>
      SMA.s0.c_req             9672832        22.77 Allocator requests<br>
      SMA.s0.c_fail                  0         0.00 Allocator failures<br>
      SMA.s0.c_bytes      637361546992   1500069.54 Bytes allocated<br>
      SMA.s0.c_freed      637360393374   1500066.83 Bytes freed<br>
      SMA.s0.g_alloc               906          .   Allocations
      outstanding<br>
      SMA.s0.g_bytes           1153618          .   Bytes outstanding<br>
      SMA.s0.g_space        1072588206          .   Bytes available<br>
      SMA.Transient.c_req       309204         0.73 Allocator requests<br>
      SMA.Transient.c_fail           0         0.00 Allocator failures<br>
      SMA.Transient.c_bytes    212330558       499.73 Bytes allocated<br>
      SMA.Transient.c_freed    212330558       499.73 Bytes freed<br>
      SMA.Transient.g_alloc            0          .   Allocations
      outstanding<br>
      SMA.Transient.g_bytes            0          .   Bytes outstanding<br>
      SMA.Transient.g_space            0          .   Bytes available<br>
      VBE.default(172.29.101.121,,8080).vcls            1          .  
      VCL references<br>
      VBE.default(172.29.101.121,,8080).happy           0          .  
      Happy health probes</small><br>
    <br>
    ------------------------------<br>
    acceptor_sleep_decay       0.900000 []<br>
    acceptor_sleep_incr        0.001000 [s]<br>
    acceptor_sleep_max         0.050000 [s]<br>
    auto_restart               on [bool]<br>
    ban_dups                   on [bool]<br>
    ban_lurker_sleep           0.010000 [s]<br>
    between_bytes_timeout      60.000000 [s]<br>
    cc_command                 "exec gcc -std=gnu99  -pthread -fpic
    -shared -Wl,-x -o %o %s"<br>
    cli_buffer                 8192 [bytes]<br>
    cli_timeout                10 [seconds]<br>
    clock_skew                 10 [s]<br>
    connect_timeout            0.700000 [s]<br>
    critbit_cooloff            180.000000 [s]<br>
    default_grace              10.000000 [seconds]<br>
    default_keep               0.000000 [seconds]<br>
    default_ttl                30.000000 [seconds]<br>
    diag_bitmap                0x0 [bitmap]<br>
    esi_syntax                 0 [bitmap]<br>
    expiry_sleep               1.000000 [seconds]<br>
    fetch_chunksize            128 [kilobytes]<br>
    fetch_maxchunksize         262144 [kilobytes]<br>
    first_byte_timeout         60.000000 [s]<br>
    gzip_level                 6 []<br>
    gzip_memlevel              8 []<br>
    gzip_stack_buffer          32768 [Bytes]<br>
    gzip_tmp_space             0 []<br>
    gzip_window                15 []<br>
    http_gzip_support          on [bool]<br>
    http_max_hdr               64 [header lines]<br>
    http_range_support         on [bool]<br>
    http_req_hdr_len           8192 [bytes]<br>
    http_req_size              32768 [bytes]<br>
    http_resp_hdr_len          8192 [bytes]<br>
    http_resp_size             32768 [bytes]<br>
    listen_address             0.0.0.0:10300<br>
    listen_depth               1024 [connections]<br>
    log_hashstring             on [bool]<br>
    log_local_address          off [bool]<br>
    lru_interval               2 [seconds]<br>
    max_esi_depth              5 [levels]<br>
    max_restarts               4 [restarts]<br>
    nuke_limit                 50 [allocations]<br>
    ping_interval              3 [seconds]<br>
    pipe_timeout               60 [seconds]<br>
    prefer_ipv6                off [bool]<br>
    queue_max                  100 [%]<br>
    rush_exponent              3 [requests per request]<br>
    saintmode_threshold        10 [objects]<br>
    send_timeout               60 [seconds]<br>
    sess_timeout               5 [seconds]<br>
    sess_workspace             65536 [bytes]<br>
    session_linger             0 [ms]<br>
    session_max                100000 [sessions]<br>
    shm_reclen                 255 [bytes]<br>
    shm_workspace              8192 [bytes]<br>
    shortlived                 10.000000 [s]<br>
    syslog_cli_traffic         on [bool]<br>
    thread_pool_add_delay      2 [milliseconds]<br>
    thread_pool_add_threshold  2 [requests]<br>
    thread_pool_fail_delay     200 [milliseconds]<br>
    thread_pool_max            1000 [threads]<br>
    thread_pool_min            60 [threads]<br>
    thread_pool_purge_delay    1000 [milliseconds]<br>
    thread_pool_stack          unlimited [bytes]<br>
    thread_pool_timeout        120 [seconds]<br>
    thread_pool_workspace      65536 [bytes]<br>
    thread_pools               2 [pools]<br>
    thread_stats_rate          10 [requests]<br>
    vcc_err_unref              on [bool]<br>
    vcl_trace                  off [bool]<br>
    waiter                     default (epoll, poll)<br>
    <br>
    <br>
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