[squid-users] Sudden but sustained high bandwidth usage

Heiler Bemerguy heiler.bemerguy at cinbesa.com.br
Mon Mar 7 18:38:49 UTC 2016


skyrocketing = using our maximum link download bandwidth.
This machine is only proxying. Not being a firewall, not a router, nor a 
gateway. It has access to the internet through our gateway/firewall 
(pfsense).
Lots of LAN clients are connected to the proxy, this is their only way 
to the internet. 1 interface, debian linux. EXT4 FS. CPU/MEM usage is 
always stable.
Clients use it explicitly or via wpad. Never transparently. Now I'm 
using 3 workers, because 1 is not enough and we have spare cores.
It's a VM machine with netapp storage. lots of raid disks.
SQUID was running perfectly without cache_dirs.

I think squid is downloading and redownloading the same files over and 
over again because: 1- these are segmented downloads and 
range_offset_limit is set to NONE for these files. 2- it can't store the 
downloaded files on the cache but I don't know why!

1457358960.737   8399 10.23.0.63 *TCP_SWAPFAIL_MISS*/206 1058138 GET 
http://au.download.windowsupdate.com/c/msdownload/update/software/uprl/2013/10/ie11-windows6.1-x64-en-us_ddec9ddc256ffa7d97831af148f6cc45130c6857.exe 
- HIER_DIRECT/201.30.251.43 application/octet-stream
1457358987.869  22464 10.88.10.5 *TCP_SWAPFAIL_MISS*/206 1416417 GET 
http://au.download.windowsupdate.com/d/msdownload/update/software/secu/2016/02/ie11-windows6.1-kb3141092-x64_0f7a98b9dc9f5c7ac73f6f543bf004a15e4d7be8.psf 
- HIER_DIRECT/201.30.251.26 application/octet-stream

Squid Object Cache: Version 3.5.15-20160301-r13999
Build Info:
Service Name: squid
Start Time:     Fri, 04 Mar 2016 21:15:47 GMT
Current Time:   Mon, 07 Mar 2016 18:14:37 GMT
Connection information for squid:
         Number of clients accessing cache:      4543
         Number of HTTP requests received:       7305505
         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:   1765.1
         Average ICP messages per minute since start:    0.0
         Select loop called: 365044476 times, 11.146 ms avg
Cache information for squid:
         Hits as % of all requests:      5min: 22.0%, 60min: 21.2%
         Hits as % of bytes sent:        5min: 3.9%, 60min: 7.3%
         Memory hits as % of hit requests:       5min: 2.5%, 60min: 2.9%
         Disk hits as % of hit requests: 5min: 28.1%, 60min: 26.8%
         Storage Swap size:      179951936 KB
         Storage Swap capacity:  45.1% used, 54.9% free
         Storage Mem size:       4194176 KB
         Storage Mem capacity:   100.0% used,  0.0% free
         Mean Object Size:       46.07 KB
         Requests given to unlinkd:      0
Median Service Times (seconds)  5 min    60 min:
         HTTP Requests (All):   0.06514  0.07007
         Cache Misses:          0.09730  0.10075
         Cache Hits:            0.00055  0.00055
         Near Hits:             0.06521  0.06757
         Not-Modified Replies:  0.00055  0.00055
         DNS Lookups:           0.00019  0.00019
         ICP Queries:           0.00000  0.00000
Resource usage for squid:
         UP Time:        248329.183 seconds
         CPU Time:       21525.705 seconds
         CPU Usage:      8.67%
         CPU Usage, 5 minute avg:        52.35%
         CPU Usage, 60 minute avg:       47.90%
         Maximum Resident Size: 85809792 KB
         Page faults with physical i/o: 104
Memory accounted for:
         Total accounted:       164356 KB
         memPoolAlloc calls: 1801863396
         memPoolFree calls:  1811836496
File descriptor usage for squid:
         Maximum number of file descriptors:   81920
         Largest file desc currently in use:   6157
         Number of file desc currently in use: 8216
         Files queued for open:                   0
         Available number of file descriptors: 73704
         Reserved number of file descriptors:   500
         Store Disk files open:                  11
Internal Data Structures:
          25054 StoreEntries
            391 StoreEntries with MemObjects
          96086 Hot Object Cache Items
         3905959 on-disk objects

Best Regards,

-- 
Heiler Bemerguy - (91) 98151-4894
Assessor Técnico - CINBESA (91) 3184-1751


Em 07/03/2016 14:33, Eliezer Croitoru escreveu:
> On 07/03/2016 16:29, Heiler Bemerguy wrote:
>> We're still getting all these SWAPFAIL and our link is
>> skyrocketing...... please help! I think it didn't happen on older
>> versions (.14 and below)
>
> Hey,
>
> What do you mean by skyrocketing?? like in the graph??
> Also it is not clear to me something about the machine, is this 
> machine a FW\ROUTER\GW?
> If so is it for a lan?
> How many interface this machine has?
> Is it a pfsense? if so what version?
> What is the FS used for the cache directories?
> Did you also measured CPU when you see the spikes? if so what is it?
> How clients access the proxy service? transparently or using a browser 
> setings or WPAD with dhcp settings?
> Also I have seen you are using 2 workers, is it because one worker 
> doesn't seem to do the job?
> Did you tried to change the values of:
> cache_swap_low 98
> cache_swap_high 99
>
> from this high to lower numbers such as:
> cache_swap_low 90
> cache_swap_high 95
>
> or even lower?
> cache_swap_low 80
> cache_swap_high 85
>
> I am unsure about this since in the docs at:
> http://www.squid-cache.org/Doc/config/cache_swap_low/
> http://www.squid-cache.org/Doc/config/cache_swap_high/
>
> the ROCK storage is not mentioned.
>
> Also on what hardware are you running? what disks?
>
> All the above are important and in your case it is possible that there 
> is something wrong in how the network is planned or the software doing 
> something wrong.
>
> In scenarios like this I offer to verify two things:
> - test what happens when you disable disk cache.(from CPU, bandwidth, 
> DISK aspect)
> - dump the cache manager info page to see basic statistics about the 
> proxy traffic using: 
> http:/cache_ip_or_visiblie_host_name:3128/squid-internal-mgr/info
>
> For scenarios like this I started working on a logging\monitoring 
> service\script that will run in the background of the machine and will 
> dump content of some statistics to enable couple squid developers eyes 
> to see these and then have a better understanding the nature of the 
> issue.
> For now the script\service is not ready and will not be able to help 
> us so we need these dumps and information..
>
> Eliezer
> _______________________________________________
> squid-users mailing list
> squid-users at lists.squid-cache.org
> http://lists.squid-cache.org/listinfo/squid-users

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