Varnish burns the CPU and eat the RAM
Romain LE DISEZ
romain.ledisez at netensia.fr
Wed Mar 2 17:46:22 CET 2011
Hello all,
I'm pretty new to Varnish. I'm deploying it because one of our customer
is going to have a special event and the website is pretty slow (I'm
working for an Internet hosting company). We are expecting more than
1000 requests per seconds.
From what I read here and there, this should not be a problem for
Varnish.
My problem is that when Varnish is using cache ("deliver", as opposed to
"pass"), the CPU consumption increases drasticaly, also the RAM.
The server is a Xeon QuadCore 2.5Ghz, 8GB of RAM.
With a simple test like this (robots.txt = 300 bytes) :
ab -r -n 1000000 -c 1000 http://www.customer1.com/robots.txt
CPU consumption is fluctuating between 120% and 160%.
Second point is that Varnish consumes all the memory. Trying to limit
that, I made a tmpfs mountpoint of 3G :
mount -t tmpfs -o size=3g tmpfs /mnt/varnish/
But varnish continues to consume all the memory
My configuration is attached to this mail. Varnish is launched like
this :
/usr/sbin/varnishd -P /var/run/varnish.pid
-a :80
-f /etc/varnish/default.vcl
-T 127.0.0.1:6082
-t 120
-w 120,120,120
-u varnish -g varnish
-S /etc/varnish/secret
-s file,/mnt/varnish/varnish_storage.bin,100%
-p thread_pools 4
I also tried to launch it with parameter "-h classic"
It is installed on a Centos 5 up to date, with lastest RPMs provided by
the varnish repository.
If I put a return (pass) in vcl_fetch, everything is fine (except the
backend server, of course). It makes me think, with my little knowledges
of Varnish, that the problem is in the delivering from cache.
Output of "varnishstat -1", when running ab, is attached.
Thanks for your help.
--
Romain LE DISEZ
-------------- next part --------------
backend customer1 {
.host = "customer1.hoster.net";
.port = "80";
}
sub vcl_recv {
#
# Normalisation des URL
#
# Normaliser les URL envoyés par curls -X et LWP
if( req.url ~ "^http://" ) {
set req.url = regsub(req.url, "http://[^/]*", "");
}
# Normaliser l'hôte (domain.tldx -> www.domain.tld)
if( req.http.host == "customer1.com" || req.http.host ~ "^(www\.)?customer1\.net$" ) {
set req.http.redir = "http://www.customer1.com" req.url;
error 750 req.http.redir;
}
#
# Configuration des sites
#
# Règles spécifiques à Customer1
if( req.http.host == "www.customer1.com" ) {
set req.backend = customer1;
# Supprimer l'entête Cookie envoyée par le navigateur
remove req.http.Cookie;
# OK pour le moment (voir quand la version mobile sera OK)
remove req.http.Accept;
remove req.http.Accept-Language;
remove req.http.Accept-Charset;
remove req.http.User-Agent;
}
#
# Règles génériques adaptées à tous les sites
#
# Période de grâce : continue de servir le contenu après son expiration du cache
# (par exemple le temps de refaire la requête vers le backend ou de le deplanter)
set req.grace = 3600s;
# Normaliser l'entête Accept-Encoding
if( req.http.Accept-Encoding ) {
if( req.url ~ "\.(jpg|jpeg|png|gif|gz|tgz|bz2|tbz|mp3|ogg|swf|mp4|flv)$" ) {
# Ne pas compresser les fichiers déjà compressés
remove req.http.Accept-Encoding;
} elsif( req.http.Accept-Encoding ~ "gzip" ) {
set req.http.Accept-Encoding = "gzip";
} elsif( req.http.Accept-Encoding ~ "deflate" ) {
set req.http.Accept-Encoding = "deflate";
} else {
# Supprimer les algorithmes inconnus
remove req.http.Accept-Encoding;
}
}
# Purger l'URL du cache si elle se termine par le paramètre purge
if( req.url ~ "~purge$" ) {
# Suppression du suffixe "~purge" puis purge de l'URL
set req.url = regsub(req.url, "(.*)~purge$", "\1");
purge_url( req.url );
}
}
#
# Appellé après recéption de la réponse du backend
#
sub vcl_fetch {
# Supprimer l'entête Set-Cookie envoyée par le serveur
remove beresp.http.Set-Cookie;
}
#
# Appellé avant l'envoi d'un contenu du cache
#
sub vcl_deliver {
remove resp.http.Via;
remove resp.http.X-Varnish;
remove resp.http.Server;
remove resp.http.X-Powered-By;
remove resp.http.P3P;
}
#
# "Catching" des erreurs
#
sub vcl_error {
if( obj.status == 750 ) {
set obj.http.Location = obj.response;
set obj.status = 301;
return(deliver);
}
}
-------------- next part --------------
client_conn 136529 117.80 Client connections accepted
client_drop 0 0.00 Connection dropped, no sess/wrk
client_req 136532 117.80 Client requests received
cache_hit 136531 117.80 Cache hits
cache_hitpass 0 0.00 Cache hits for pass
cache_miss 1 0.00 Cache misses
backend_conn 1 0.00 Backend conn. success
backend_unhealthy 0 0.00 Backend conn. not attempted
backend_busy 0 0.00 Backend conn. too many
backend_fail 0 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 1 0.00 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 7720 . N struct sess_mem
n_sess 18446744073709551606 . N struct sess
n_object 1 . N struct object
n_vampireobject 0 . N unresurrected objects
n_objectcore 481 . N struct objectcore
n_objecthead 481 . N struct objecthead
n_smf 3 . N struct smf
n_smf_frag 0 . N small free smf
n_smf_large 1 . N large free smf
n_vbe_conn 0 . N struct vbe_conn
n_wrk 480 . N worker threads
n_wrk_create 480 0.41 N worker threads created
n_wrk_failed 0 0.00 N worker threads not created
n_wrk_max 81 0.07 N worker threads limited
n_wrk_queue 0 0.00 N queued work requests
n_wrk_overflow 166 0.14 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 6 . 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 136429 117.71 Objects sent with write
n_objoverflow 0 0.00 Objects overflowing workspace
s_sess 136534 117.80 Total Sessions
s_req 136534 117.80 Total Requests
s_pipe 0 0.00 Total pipe
s_pass 0 0.00 Total pass
s_fetch 1 0.00 Total fetch
s_hdrbytes 30885129 26648.08 Total header bytes
s_bodybytes 41097938 35459.83 Total body bytes
sess_closed 136538 117.81 Session Closed
sess_pipeline 0 0.00 Session Pipeline
sess_readahead 0 0.00 Session Read Ahead
sess_linger 0 0.00 Session Linger
sess_herd 0 0.00 Session herd
shm_records 4233973 3653.13 SHM records
shm_writes 547445 472.34 SHM writes
shm_flushes 0 0.00 SHM flushes due to overflow
shm_cont 46002 39.69 SHM MTX contention
shm_cycles 1 0.00 SHM cycles through buffer
sm_nreq 2 0.00 allocator requests
sm_nobj 2 . outstanding allocations
sm_balloc 8192 . bytes allocated
sm_bfree 2574852096 . bytes free
sma_nreq 0 0.00 SMA allocator requests
sma_nobj 0 . SMA outstanding allocations
sma_nbytes 0 . SMA outstanding bytes
sma_balloc 0 . SMA bytes allocated
sma_bfree 0 . SMA bytes free
sms_nreq 0 0.00 SMS allocator requests
sms_nobj 0 . SMS outstanding allocations
sms_nbytes 0 . SMS outstanding bytes
sms_balloc 0 . SMS bytes allocated
sms_bfree 0 . SMS bytes freed
backend_req 1 0.00 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 136442 117.72 HCB Lookups without lock
hcb_lock 1 0.00 HCB Lookups with lock
hcb_insert 1 0.00 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 1159 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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