On Mon, 27 Jul 2009 12:14:29 -0700 (PDT), jotacekm <minuzzo@xxxxxxxxxxxx>
wrote:
Hello.
Recently we have added a lot more clientes behind a squid proxy, and now
cpu
utilizitaion is usually 70-95%. The processor is a intel dual core 2160
@
1.80GHz. Users started complaing about the speed on accessing pages, and
the
link is fine.
Here is squidclient mgr:info:
Squid Object Cache: Version 2.6.STABLE5
Start Time: Fri, 24 Jul 2009 20:19:16 GMT
Current Time: Mon, 27 Jul 2009 19:09:07 GMT
Connection information for squid:
Number of clients accessing cache: 1561
Number of HTTP requests received: 8590404
Number of ICP messages received: 0
Number of ICP messages sent: 0
Number of queued ICP replies: 0
Number of HTCP messages received: 0
Number of HTCP messages sent: 0
Request failure ratio: 0.00
Average HTTP requests per minute since start: 2021.3
2k req/min is getting close to what people report for saturation of older
2.6 forward proxies.
First performance improvement will be simply an upgrade to 2.7.
Average ICP messages per minute since start: 0.0
Select loop called: 122560206 times, 2.081 ms avg
Cache information for squid:
Request Hit Ratios: 5min: 23.0%, 60min: 21.9%
Byte Hit Ratios: 5min: 13.3%, 60min: 14.7%
Request Memory Hit Ratios: 5min: 16.3%, 60min: 17.0%
Request Disk Hit Ratios: 5min: 26.3%, 60min: 29.9%
Storage Swap size: 4609784 KB
Storage Mem size: 65692 KB
Mean Object Size: 15.67 KB
Requests given to unlinkd: 455490
Median Service Times (seconds) 5 min 60 min:
HTTP Requests (All): 1.24267 1.46131
Cache Misses: 1.54242 1.81376
Cache Hits: 0.28853 0.30459
Near Hits: 1.31166 1.62803
Not-Modified Replies: 0.23230 0.23230
DNS Lookups: 0.29097 0.31806
ICP Queries: 0.00000 0.00000
Resource usage for squid:
UP Time: 254991.358 seconds
CPU Time: 56029.670 seconds
CPU Usage: 21.97%
CPU Usage, 5 minute avg: 94.38%
CPU Usage, 60 minute avg: 93.36%
Process Data Segment Size via sbrk(): 193008 KB
Maximum Resident Size: 0 KB
Page faults with physical i/o: 70
Memory usage for squid via mallinfo():
Total space in arena: 193008 KB
Ordinary blocks: 179871 KB 6058 blks
Small blocks: 0 KB 0 blks
Holding blocks: 1080 KB 2 blks
Free Small blocks: 0 KB
Free Ordinary blocks: 13136 KB
Total in use: 180951 KB 93%
Total free: 13136 KB 7%
Total size: 194088 KB
Memory accounted for:
Total accounted: 111416 KB
memPoolAlloc calls: 973288506
memPoolFree calls: 972077571
File descriptor usage for squid:
Maximum number of file descriptors: 4096
Largest file desc currently in use: 1604
Number of file desc currently in use: 1308
Files queued for open: 0
Available number of file descriptors: 2788
Reserved number of file descriptors: 100
Store Disk files open: 30
IO loop method: epoll
Internal Data Structures:
300182 StoreEntries
14733 StoreEntries with MemObjects
14414 Hot Object Cache Items
294106 on-disk objects
And here is part of of squid.conf:
http_port 3128
visible_hostname xxx
hierarchy_stoplist cgi-bin ?
acl QUERY urlpath_regex cgi-bin \?
cache deny QUERY
_after_ upgrading to the most recent 2.6 or a 2.7. Remove the QUERY
entries
above.
acl apache rep_header Server ^Apache
broken_vary_encoding allow apache
access_log /var/log/squid/access.log squid
cache_store_log none
hosts_file /etc/hosts
#
----------------------------------------------------------------------------------------------------------
cache_mem 64 MB
cache_dir ufs /var/spool/squid 5000 50 256
#1 change that to aufs if using a Linux or variants. diskd if using BSD
or
variants. Change to Linux or BSD if using Windows.
#2 up the cache size as much as you can. Local objects are much faster to
retrieve than external ones.
The more local objects you can store the faster Squid responds.
From my experience its around an order of magnitude or more req/sec
handled
from cache as from network.
Memory cache is better for speed than disk, but can be lost more easily
and
you can get bigger cache total spending RAM on indexes and disk on object
storage.
After the upgrade to 2.7 you have access to a stable COSS system which is
very much more efficient for the small files. It's worth a try.
cache_replacement_policy heap LFUDA
maximum_object_size 51200 KB
There is good evidence that the web now has a lot of traffic in the 2MB to
250MB range from multimedia objects.
This will bear investigating in your traffic and see if the limit above is
still good.
maximum_object_size_in_memory 64 KB
memory_replacement_policy heap GDSF
logfile_rotate 3
#
----------------------------------------------------------------------------------------------------------
refresh_pattern ^ftp: 1440 20% 10080
refresh_pattern ^gopher: 1440 0% 1440
Add:
refresh_pattern -i (/cgi-bin/|\?) 0 0% 0
refresh_pattern . 0 20% 4320
acl all src 0.0.0.0/0.0.0.0
acl manager proto cache_object
acl localhost src 127.0.0.1/255.255.255.255
acl to_localhost dst 127.0.0.0/8
max_open_disk_fds 2046
Definitely raise that. Your stats show that many _new_ requests arriving
every second.
Each single request eats 2-3 FD and may last from seconds to hours.
# timeouts
connect_timeout 30 seconds
shutdown_lifetime 5 seconds
forward_timeout 2 minutes
pconn_timeout 30 seconds
You _want_ pconn to last a fairly long while. There is no CPU or bandwidth
overhead.
Possibly also enabling client and server persistent connections.
persistent_request_timeout 1 minute
request_timeout 2 minute
Is there anything that i can do to lower the cpu utilization, or do i
have
to upgrade the hardware?
There are a number of other perfromance optimizations possible within the
build options and in other squid.conf settings. You don't say what they
are
set at, so we can't suggest any right now.
Amos
