median service time

Hi,

We are still running Squid-2.0 Patch2 on a Sparc Server 250 with 1Gbytes
RAM and Solaris 2.6 and is connected to the LAN using an hme interface
(100Mbits full duplex). It is connected to 6 Mbits link (with between a
firewall) loaded around 5Mbits. Sometimes the median service time climb to
more 4 s as you can see below.

My /etc/system contains :

set rlim_fd_max = 4096
set rlim_fd_cur = 2048
set sq_max_size = 1024
set tcp:tcp_conn_hash_size = 32768
set priority_paging = 1
set ncsize = 25000

The cache is as follows :

/Cache1 : 3000 Mb (4.2Gbytes HD)
/Cache2 : 6500 Mb (9 Gbytes HD)
/Cache3 : 6500 Mb (9 Gbytes HD)

Via the /etc/resolv.conf, i have 3 DNS servers with at least the first
dedicated to Squid. As you can see, the DNS lookups are not the problem.

From my experience, the problem does not seem to be completly related to
the number of request per second. Sometimes even with 49 req/s, the
counters are less than 1s, specially the "Cache Hits" one.

One thing strange from the numbers below is :
client_http.kbytes_out = 406.849072/sec
server.all.kbytes_in = 493.829955/sec

It seems when these two numbers become closer, the response time counters
are back to normal values.

I would like to try to set the max_open_disk_fds in squid.conf, but have no
idea what value to use.

Does anybody know what is happening ?
Thanks for any help.
Alain Sabban

                   -------------------------------------

General runtime info

Connection information for squid:
        Number of clients accessing cache: 733
        Number of HTTP requests received: 144848
        Number of ICP messages received: 0
        Number of ICP messages sent: 0
        Number of queued ICP replies: 0
        Request failure ratio: 0.00%
        HTTP requests per minute: 2777.6
        ICP messages per minute: 0.0
        Select loop called: 84662 times, 36.958 ms avg
Cache information for squid:
        Storage Swap size: 10604828 KB
        Storage Mem size: 116648 KB
        Storage LRU Expiration Age: 365.00 days
        Mean Object Size: 13.03 KB
        Requests given to unlinkd: 11164
Median Service Times (seconds) 5 min 60 min:
        HTTP Requests (All): 4.54239 4.07741
        Cache Misses: 4.79440 4.54239
        Cache Hits: 3.86308 3.66001
        Near Hits: 4.79440 4.30363
        Not-Modified Replies: 3.66001 3.46762
        DNS Lookups: 0.26619 0.24351
        ICP Queries: 0.00000 0.00000
Resource usage for squid:
        UP Time: 3128.972 seconds
        CPU Time: 825.510 seconds
        CPU Usage: 26.38%
        CPU Usage, 5 minute avg: 28.79%
        CPU Usage, 60 minute avg: 26.38%
        Maximum Resident Size: 0 KB
        Page faults with physical i/o: 33687
Memory usage for squid via mallinfo():
        Total space in arena: 230950 KB
        Ordinary blocks: 230159 KB 2139 blks
        Small blocks: 0 KB 0 blks
        Holding blocks: 848 KB 2 blks
        Free Small blocks: 0 KB
        Free Ordinary blocks: 790 KB
        Total in use: 231007 KB 100%
        Total free: 790 KB 0%
Memory accounted for:
        Total accounted: 201371 KB
File descriptor usage for squid:
        Maximum number of file descriptors: 4096
        Largest file desc currently in use: 1085
        Number of file desc currently in use: 970
        Available number of file descriptors: 3126
        Reserved number of file descriptors: 100
        Disk files open: 76
Internal Data Structures:
        818984 StoreEntries
         24346 StoreEntries with MemObjects
         19910 Hot Object Cache Items
        813982 Filemap bits set
        813618 on-disk objects

5 minutes counters

sample_start_time = 939125111.600115 (Tue, 05 Oct 1999 12:05:11 GMT)
sample_end_time = 939125412.148914 (Tue, 05 Oct 1999 12:10:12 GMT)
client_http.requests = 50.241425/sec
client_http.hits = 16.143801/sec
client_http.errors = 0.000000/sec
client_http.kbytes_in = 21.793466/sec
client_http.kbytes_out = 406.849072/sec
client_http.all_median_svc_time = 4.542394 seconds
client_http.miss_median_svc_time = 5.060391 seconds
client_http.nm_median_svc_time = 3.660014 seconds
client_http.nh_median_svc_time = 4.794403 seconds
client_http.hit_median_svc_time = 3.863080 seconds
server.all.requests = 34.446985/sec
server.all.errors = 0.000000/sec
server.all.kbytes_in = 493.829955/sec
server.all.kbytes_out = 17.710934/sec
server.http.requests = 33.841426/sec
server.http.errors = 0.000000/sec
server.http.kbytes_in = 426.240266/sec
server.http.kbytes_out = 17.388191/sec
server.ftp.requests = 0.043254/sec
server.ftp.errors = 0.000000/sec
server.ftp.kbytes_in = 65.566723/sec
server.ftp.kbytes_out = 0.009982/sec
server.other.requests = 0.562305/sec
server.other.errors = 0.000000/sec
server.other.kbytes_in = 2.019639/sec
server.other.kbytes_out = 0.316088/sec
icp.pkts_sent = 0.000000/sec
icp.pkts_recv = 0.000000/sec
icp.queries_sent = 0.000000/sec
icp.replies_sent = 0.000000/sec
icp.queries_recv = 0.000000/sec
icp.replies_recv = 0.000000/sec
icp.replies_queued = 0.000000/sec
icp.query_timeouts = 0.000000/sec
icp.kbytes_sent = 0.000000/sec
icp.kbytes_recv = 0.000000/sec
icp.q_kbytes_sent = 0.000000/sec
icp.r_kbytes_sent = 0.000000/sec
icp.q_kbytes_recv = 0.000000/sec
icp.r_kbytes_recv = 0.000000/sec
icp.query_median_svc_time = 0.000000 seconds
icp.reply_median_svc_time = 0.000000 seconds
dns.median_svc_time = 0.254601 seconds
unlink.requests = 4.555001/sec
page_faults = 9.695597/sec
select_loops = 10.078230/sec
select_fds = 728.963153/sec
average_select_fd_period = 0.001369/fd
median_select_fds = 67.983398
swap_files_cleaned = 0.003327/sec
aborted_requests = 1.573788/sec
syscalls.polls = 19.540920/sec
syscalls.disk.opens = 32.227712/sec
syscalls.disk.closes = 32.204421/sec
syscalls.disk.reads = 24.711461/sec
syscalls.disk.writes = 108.345134/sec
syscalls.disk.seeks = 0.515723/sec
syscalls.disk.unlinks = 0.003327/sec
syscalls.sock.accepts = 45.327082/sec
syscalls.sock.sockets = 22.638587/sec
syscalls.sock.connects = 22.472224/sec
syscalls.sock.binds = 22.522133/sec
syscalls.sock.closes = 60.698962/sec
syscalls.sock.reads = 299.375676/sec
syscalls.sock.writes = 260.560016/sec
syscalls.sock.recvfroms = 0.000000/sec
syscalls.sock.sendtos = 0.000000/sec
cpu_time = 85.460000 seconds
wall_time = 300.548799 seconds
cpu_usage = 28.434650%
Received on Tue Oct 05 1999 - 07:03:59 MDT