Hi Everyone, I am seeing a situation similar to :
http://www.varnish-cache.org/lists/pipermail/varnish-misc/2011-January/005351.html(Connections Dropped Under Load) http://www.varnish-cache.org/lists/pipermail/varnish-misc/2010-December/005258.html(Hanging Connections) I have httperf loading a varnish cache with never-expire content. While the load is on, other browser/wget requests to the varnish server get delayed to 10+ seconds. Any ideas what could be happening? ssh doesn't seem to be impacted. So, is it some kind of thread problem? In production, I see a similar situation with around 1000 req/second load. I am running varnishd with the following command line options (as per http://kristianlyng.wordpress.com/2009/10/19/high-end-varnish-tuning/): sudo varnishd -f /etc/varnish/default.vcl -s malloc,5G -T 127.0.0.1:2000 -a 0.0.0.0:80 -p thread_pools=8 -p thread_pool_min=100 -p thread_pool_max=5000 -p thread_pool_add_delay=2 -p cli_timeout=25 -p session_linger=100 -p lru_interval=20 -t 31536000 I am on Ubuntu Lucid 64 bit Amazon EC2 C1.XLarge with 8 processing units. My network sysctl parameters are tuned according to: http://varnish-cache.org/trac/wiki/Performance fs.file-max = 360000 net.ipv4.ip_local_port_range = 1024 65536 net.core.rmem_max = 16777216 net.core.wmem_max = 16777216 net.ipv4.tcp_rmem = 4096 87380 16777216 net.ipv4.tcp_wmem = 4096 65536 16777216 net.ipv4.tcp_fin_timeout = 3 net.core.netdev_max_backlog = 30000 net.ipv4.tcp_no_metrics_save = 1 net.core.somaxconn = 262144 net.ipv4.tcp_syncookies = 0 net.ipv4.tcp_max_orphans = 262144 net.ipv4.tcp_max_syn_backlog = 262144 net.ipv4.tcp_synack_retries = 2 net.ipv4.tcp_syn_retries = 2 Any help would be greatly appreciated
client_conn 12408 8.19 Client connections accepted client_drop 0 0.00 Connection dropped, no sess/wrk client_req 5549280 3662.89 Client requests received cache_hit 5543904 3659.34 Cache hits cache_hitpass 0 0.00 Cache hits for pass cache_miss 5376 3.55 Cache misses backend_conn 5373 3.55 Backend conn. success backend_unhealthy 0 0.00 Backend conn. not attempted backend_busy 0 0.00 Backend conn. too many backend_fail 3 0.00 Backend conn. failures backend_reuse 0 0.00 Backend conn. reuses backend_toolate 0 0.00 Backend conn. was closed backend_recycle 0 0.00 Backend conn. recycles backend_unused 0 0.00 Backend conn. unused fetch_head 0 0.00 Fetch head fetch_length 5373 3.55 Fetch with Length fetch_chunked 0 0.00 Fetch chunked fetch_eof 0 0.00 Fetch EOF fetch_bad 0 0.00 Fetch had bad headers fetch_close 0 0.00 Fetch wanted close fetch_oldhttp 0 0.00 Fetch pre HTTP/1.1 closed fetch_zero 0 0.00 Fetch zero len fetch_failed 0 0.00 Fetch failed n_sess_mem 798 . N struct sess_mem n_sess 548 . N struct sess n_object 5373 . N struct object n_vampireobject 0 . N unresurrected objects n_objectcore 5806 . N struct objectcore n_objecthead 5806 . N struct objecthead n_smf 0 . N struct smf n_smf_frag 0 . N small free smf n_smf_large 0 . N large free smf n_vbe_conn 0 . N struct vbe_conn n_wrk 800 . N worker threads n_wrk_create 800 0.53 N worker threads created n_wrk_failed 0 0.00 N worker threads not created n_wrk_max 0 0.00 N worker threads limited n_wrk_queue 0 0.00 N queued work requests n_wrk_overflow 0 0.00 N overflowed work requests n_wrk_drop 0 0.00 N dropped work requests n_backend 1 . N backends n_expired 0 . N expired objects n_lru_nuked 0 . N LRU nuked objects n_lru_saved 0 . N LRU saved objects n_lru_moved 74099 . N LRU moved objects n_deathrow 0 . N objects on deathrow losthdr 0 0.00 HTTP header overflows n_objsendfile 0 0.00 Objects sent with sendfile n_objwrite 5543132 3658.83 Objects sent with write n_objoverflow 0 0.00 Objects overflowing workspace s_sess 12407 8.19 Total Sessions s_req 5549280 3662.89 Total Requests s_pipe 0 0.00 Total pipe s_pass 0 0.00 Total pass s_fetch 5373 3.55 Total fetch s_hdrbytes 1245394845 822042.80 Total header bytes s_bodybytes 13448598673 8876962.82 Total body bytes sess_closed 43 0.03 Session Closed sess_pipeline 0 0.00 Session Pipeline sess_readahead 0 0.00 Session Read Ahead sess_linger 5549262 3662.88 Session Linger sess_herd 1431702 945.02 Session herd shm_records 162564756 107303.47 SHM records shm_writes 7031015 4640.93 SHM writes shm_flushes 0 0.00 SHM flushes due to overflow shm_cont 138344 91.32 SHM MTX contention shm_cycles 60 0.04 SHM cycles through buffer sm_nreq 0 0.00 allocator requests sm_nobj 0 . outstanding allocations sm_balloc 0 . bytes allocated sm_bfree 0 . bytes free sma_nreq 10746 7.09 SMA allocator requests sma_nobj 10746 . SMA outstanding allocations sma_nbytes 17538168 . SMA outstanding bytes sma_balloc 17538168 . SMA bytes allocated sma_bfree 0 . SMA bytes free sms_nreq 3 0.00 SMS allocator requests sms_nobj 0 . SMS outstanding allocations sms_nbytes 0 . SMS outstanding bytes sms_balloc 1254 . SMS bytes allocated sms_bfree 1254 . SMS bytes freed backend_req 5373 3.55 Backend requests made n_vcl 1 0.00 N vcl total n_vcl_avail 1 0.00 N vcl available n_vcl_discard 0 0.00 N vcl discarded n_purge 1 . N total active purges n_purge_add 1 0.00 N new purges added n_purge_retire 0 0.00 N old purges deleted n_purge_obj_test 0 0.00 N objects tested n_purge_re_test 0 0.00 N regexps tested against n_purge_dups 0 0.00 N duplicate purges removed hcb_nolock 5540904 3657.36 HCB Lookups without lock hcb_lock 5375 3.55 HCB Lookups with lock hcb_insert 5373 3.55 HCB Inserts esi_parse 0 0.00 Objects ESI parsed (unlock) esi_errors 0 0.00 ESI parse errors (unlock) accept_fail 0 0.00 Accept failures client_drop_late 0 0.00 Connection dropped late uptime 1515 1.00 Client uptime backend_retry 0 0.00 Backend conn. retry dir_dns_lookups 0 0.00 DNS director lookups dir_dns_failed 0 0.00 DNS director failed lookups dir_dns_hit 0 0.00 DNS director cached lookups hit dir_dns_cache_full 0 0.00 DNS director full dnscache fetch_1xx 0 0.00 Fetch no body (1xx) fetch_204 0 0.00 Fetch no body (204) fetch_304 0 0.00 Fetch no body (304)
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