Re: [squid-users] Squid stops responding-LTSP and WinXP clients

On Thu, Sep 10, 2009 at 4:31 PM, Amos Jeffries <squid3_at_treenet.co.nz> wrote:
> Avinash Rao wrote:
>>
>> On Thu, Sep 10, 2009 at 10:54 AM, Avinash Rao <avinash.aol_at_gmail.com>
>> wrote:
>>>
>>> On Wed, Sep 9, 2009 at 5:45 PM, Amos Jeffries <squid3_at_treenet.co.nz>
>>> wrote:
>>>>
>>>> Avinash Rao wrote:
>>>>>
>>>>> Dear all,
>>>>>
>>>>> I am sure this question would have been posted many times. I read a
>>>>> few threads, but my requirement or setup is a bit different. I am
>>>>> running Squid2.6stable18 on Ubuntu Server 8.04 Server 64-bit installed
>>>>> on Sun Fire X4150 Server with 8GB RAM + 8 SAS HDD's - RAID 5 + 2 Quad
>>>>> Core Intel Xeon Processors.
>>>>>
>>>>> I have both LTSP and WinXP clients using Squid. Many times i have
>>>>> noticed, squid stops responding, the browser keeps trying to connect
>>>>> and i don't see any error in cache.log or store.log. My only way out
>>>>> is to restart squid.
>>>>
>>>> Usually means Squid is doing something with its on-disk storage.
>>>>
>>>>> I read through cache_mem, my current configuration is 100MB, �i
>>>>> changed it to 128MB, but squid couldn't start saying the cache_mem is
>>>>> more than cache_disk size.
>>>>>
>>>>> Why does this happen and what is the recommended configuration for the
>>>>> hardware i have?
>>>>
>>>> You are missing a cache_dir option. Which means Squid-2 will be using
>>>> the
>>>> default and very inefficient 100 MB ufs formatted storage.
>>>>
>>>> Squid-3.1 and later are the only releases of Squid where cache_dir can
>>>> be
>>>> fully removed from the config.
>>>>
>>>> Either define a cache_dir to use the disks or setup the "null" cache_dir
>>>> type for memory-only storage.
>>>>
>>>>> squid.conf: Please donot compare this config to my other posts, as
>>>>> this is on a different server and it has a very basic configuration.
>>>>>
>>>>> visible_hostname sunserver
>>>>> hierarchy_stoplist cgi-bin ?
>>>>> acl QUERY urlpath_regex cgi-bin \?
>>>>> no_cache deny QUERY
>>>>
>>>> Drop 'no_cache' use instead:
>>>> �cache deny QUERY
>>>>
>>>>> hosts_file /etc/hosts
>>>>> http_port 10.10.10.10:3128
>>>>> refresh_pattern ^ftp: 1440 20% 10080
>>>>> refresh_pattern ^gopher: 1440 0% 1440
>>>>> 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
>>>>> acl SSL_ports port 443 563
>>>>> acl Safe_ports port 80 � � � � � � � �# http
>>>>> acl Safe_ports port 21 � � � � � � � �# ftp
>>>>> acl Safe_ports port 443 563 � � � � � # https, snews
>>>>> acl Safe_ports port 70 � � � � � � � �# gopher
>>>>> acl Safe_ports port 210 � � � � � � � # wais
>>>>> acl Safe_ports port 1025-65535 � � � �# unregistered ports
>>>>> acl Safe_ports port 280 � � � � � � � # http-mgmt
>>>>> acl Safe_ports port 488 � � � � � � � # gss-http
>>>>> acl Safe_ports port 591 � � � � � � � # filemaker
>>>>> acl Safe_ports port 631 � � � � � � � # cups
>>>>> acl Safe_ports port 777 � � � � � � � # multiling http
>>>>> acl Safe_ports port 901 � � � � � � � # SWAT
>>>>> acl Safe_ports port 993 � � � � � � � # IMAP
>>>>> acl Safe_ports port 587 � � � � � � � # SMTP
>>>>> acl Safe_ports port 22 � � � � � � � �# SSH
>>>>> acl purge method PURGE
>>>>> acl special_urls url_regex "/etc/squid/squid-noblock.acl"
>>>>> acl extndeny url_regex -i "/etc/squid/blocks.files.acl"
>>>>> acl malware_block_list url_regex -i "/etc/squid/malware_block_list.txt"
>>>>> acl badurl url_regex -i teen orkut youtube sex mp3 mp4
>>>>> acl lan src 10.10.10.0/24
>>>>> acl stud ident_regex babu
>>>>> acl download method GET
>>>>> acl CONNECT method CONNECT
>>>>> cache_mem 100 MB
>>>>> ident_lookup_access allow all
>>>>> deny_info http://malware.hiperlinks.com.br/denied.shtml
>>>>> malware_block_list
>>>>> http_access allow manager localhost
>>>>> http_access deny manager
>>>>> http_access allow purge localhost
>>>>> http_access allow special_urls
>>>>> http_access deny extndeny download
>>>>> http_access deny extndeny
>>>>> http_access deny purge
>>>>> http_access deny !Safe_ports
>>>>> http_access deny CONNECT !SSL_ports
>>>>> http_access deny badurl
>>>>> http_access deny malware_block_list
>>>>> http_access allow localhost
>>>>> http_access allow lan
>>>>> http_access deny all
>>>>> http_reply_access allow all
>>>>> icp_access allow all
>>>>> coredump_dir /var/spool/squid
>>>>>
>>>>>
>>>>> Many Thanks
>>>>> Avinash
>>>>
>>>> --
>>>> Please be using
>>>> �Current Stable Squid 2.7.STABLE6 or 3.0.STABLE18
>>>> �Current Beta Squid 3.1.0.13
>>>>
>>> Thank you all for the information. I read the documentation.
>>> To begin with I have set cache_dir to 256MB and cache_mem also to 256
>>> MB. Which takes the precedence? I guess the pages are stored/retrieved
>>> from the RAM. Does this setting mean that, once 256MB is reached in
>>> RAM it will start storing the pages in cache_dir?
>>>
>>> Thanks,
>>> Avinash
>>>
>>
>> Hi Guys,
>>
>> I just tested it, but it was pretty slow, the page was not loading
>> only. Strange coz,
>> the cache_mem is increased to 256MB and its still slow? How does this
>> work?
>
> Everything gets stuffed into cache_mem first.
> �- objects which are labeled as too large for memory, or those unlabeled
> which grow too large, get pushed to disk. This happens even if not
> completely downloaded yet, which can be one cause of slowness on big stuff.
> �- objects which have not been used longest get pushed to disk when more
> memory space is needed.
> �- all memory objects are pushed to disk during shutdown, restart,
> reconfigure.
>
>> According to the squid Documentation, i recommended size for cache_dir
>> is 7000 or 8000!
>>
>> I set cache_dir to null /tmp and i could see a lot of difference and
>> it worked pretty well.
>
> Seems to me that the issue was some things being sent to disk storage.
> Combined with severe speed problems reading/waiting from that disk storage.
>
> You said you have RAID5 so I'm not surprised its slow.
> RAID and Squid do NOT play well together. Squid treats the disk as
> random-access media using as many access threads as it can obtain in
> parallel. Doing 4KB chunk operations.
>
> Amos
> --
> Please be using
> �Current Stable Squid 2.7.STABLE6 or 3.0.STABLE18
> �Current Beta Squid 3.1.0.13
>

Thank you for the explanation. Its working well now, LTSP users are
satisfied with the speed. I awaiting feedback from Windows Users as
more than 25users login at the same time and use Internet.

Cheers
Avinash
Received on Fri Sep 11 2009 - 15:26:13 MDT