Page 2 of 3 FirstFirst 123 LastLast
Results 11 to 20 of 24

Thread: Long loading times in webaccess

  1. #11

    Re: Long loading times in webaccess

    Hi sverre,


    The administrator login is slower than those of normal users. If this slowness is only administrator users, it is normal because the webaccess also brings to users excluded in the left menu.
    ================================
    Diego Altheman - Brasil/SP - ADTsys

  2. #12
    Member
    Join Date
    Nov 2008
    Location
    Falköping, Sweden
    Posts
    75

    Re: Long loading times in webaccess

    OK, I see

    Actually the non-administrators is experiencing the longest loading times...

  3. #13
    Junior Member
    Join Date
    Jan 2009
    Posts
    17

    Re: Long loading times in webaccess

    There is some documentation for tuning mysql and zarafa but for environments with webaccess its very likely that you need to understand and tune apache2 - sadly there is no advice to do in zarafa-docs.

    So, if you see long response times in webaccess and you are sure its not because your mysql db is slow or your zarafa-server process is saturated you should check your apache2 configuration.

    First check the load of mysql and zarafa-server process (with a tool like "top")
    If load is low and response in webaccess is slow its likely that your apache2 config causes long waits.

    Look into the /etc/apache2/apache2.conf config file for these values:
    (1) KeepAlive (on or off)
    (2) KeepAliveTimeout (seconds)
    (3) in section prefork MPM : MaxClients (number)

    First off "MaxClients".
    It defines the max number of apache2 processes for servicing browser requests.
    You have to know that one apache2 process serves only one browser request at a time.
    For example: You click somewhere in webaccess (maybe to open an email). Your browser transmits the request to the main apache2 process on your server. This main apache2 seeks for a "free" child apache2 to serve your request. If it cant find any, it will start a new one - but only until
    apache2 reached the "MaxClient" number of processes - otherwise it waits till a client gets free again. The child works on the request (ask zarafa for the email, wait till zarafa returns the mail, render the page and return it to your browser).

    So if you have 100 guys heavily working with webaccess at the same time and only 30 apache processes - every click in webaccess means first off to wait for a free apache process to serve your request.
    This leads to this effect of low server load and looooong load times for your workmates...

    Check in a shell with "ps -efa|grep apache2|wc -l" how many apaches are currently running.
    If its the same number than maxclients, its very likely that your webaccess feels slow , because of waiting for free apaches.


    Keepalive and Keepalivetimeout
    If Keepalive is set to ON its getting a bit more complicated.
    KeepAlive is somehow a caching of apaches, means that the apache client who served your last request keeps stuck to your browser for "keepalivetimeout" seconds - waiting for a further request. This of course improves the "felt" performance if you click rapidly one email, then the next and so on. Your browser does not have to wait for the new election of a free apache client process.
    But on the other hand it can make the overall performance very poor.
    Example:
    You have Maxclient 20 , Keepalive On , Keepalivetimeout 10
    20 people click onto an email, they all get one of the 20 apaches, these 20 apaches serve the requests and wait for 10 seconds for further requests for their "bound" browsers.
    guy 21 meanwhile clicks and..... has to wait up to 10 seconds until one of the apaches gets free again!
    If these 20 guys keep on using their webaccess heavily they will "never" release their apache client and guy 21 starves till death....


    Traps:
    Ok, you saw that your "maxclient" is too low - so why not just increase it , maybe to the amount of people working with webaccess?
    Good idea , if you have enough RAM and SWAP.... keep in mind every apache2 process needs like 40-50 MB of Ram and 200MB of swap!
    So 100 apaches would need -at least- 5GB of real RAM. And if your machine doesnt have enough (remind your zarafa-server cache and your mysql-cache!!!) it will start swapping and getting really slow.


    There is no golden way to easily solve performance problems - but check your "maxclients" first!

    If you are low on RAM and can't increase "maxclient" it to a sufficient amount , its a very good idea to switch of "KeepAlive" for this avoids the unnecessary waiting for free apaches while most of the apaches themselfes wait for further browser requests....


    thomas

  4. #14
    Member
    Join Date
    Nov 2008
    Location
    Falköping, Sweden
    Posts
    75

    Re: Long loading times in webaccess

    Thanks a lot for the detailed response. Great reading!

    I dont think that MaxClients is the problem. 150 processes are allowed but since we are only 6 people working here and KeepAlive was On there was only 12 apache-processes spawned.

    Do you think that KeepAlive = Off would speed up the overall performance? If I understood your description correctly that could be the way to go, right?

    Best regards
    Daniel

  5. #15
    Junior Member
    Join Date
    Jan 2009
    Posts
    17

    Re: Long loading times in webaccess

    Daniel,
    sorry, if you're only 6 guys working and maxclient > 6 - everybody has his "own" apache2-client.
    So keepalive=off would slightly reduce performance (really slightly in your case) because of not caching
    the clients.
    You definitly have some other problem with your performance.

    1) Have enough ram? Is your machine swapping (look for used swapspace in "top") , "used" should be almost at 0.
    2) is zarafa-server at high load?
    3) is mysql at hight load?
    4) is mysql saturating your harddisk? look at iostat -k 1 , interesting is "tps" whig means transactions per second

    thomas

  6. #16

    Re: Long loading times in webaccess

    Hi,

    I'm wondering if this is likewise the problem described in;



    Have a look at your debug.txt log file. It resides in /usr/share/zarafa-webaccess.

  7. #17
    Member
    Join Date
    Nov 2008
    Location
    Falköping, Sweden
    Posts
    75

    Re: Long loading times in webaccess

    Thanks again Thomas for your hints.

    When watching top there is nothing that indicates that there has ever been a large memory consumtion. Everything is looking pretty good.

    The zarafa-server process is never requiring much cpu, but mysql sometimes does.

    I will run iostat when we are experiencing high load again. Hopefully it could tell me something more.

  8. #18
    Member
    Join Date
    Nov 2008
    Location
    Falköping, Sweden
    Posts
    75

    Re: Long loading times in webaccess

    gduran, thanks, but I do not think these issues are related. The long loading times for us happens when checking e-mail, and the debug.txt file isn't growing particularly large.

    Regards
    Daniel

  9. #19
    Senior Member
    Join Date
    Nov 2008
    Location
    Hilden, close to Duesseldorf, NRW, Germany, Europe, Earth...
    Posts
    1,070

    Re: Long loading times in webaccess

    Hi Daniel,

    you say you experience this while checking emails. May I ask you for a bit more details?

    - Are these eMails big or have something else special?
    - Art these eMails stored inside / outside the db?
    - Do you use any online virus protection apps at server / client site?
    - If yes, which once...

    Best regards

    Andreas
    Using Zarafa 7.2.5-29, Z-Push 2.3.4 with GZip and soon again SMS Support.

  10. #20
    Member
    Join Date
    Nov 2008
    Location
    Falköping, Sweden
    Posts
    75

    Re: Long loading times in webaccess

    No big e-mail, but everything is stored inside the db. We are all running the webaccess (i.e. no antivirus on the client side) and there is no antivirus on the serverside either.

    Regards
    Daniel

Page 2 of 3 FirstFirst 123 LastLast

Similar Threads

  1. OpenSuse 12.1 webaccess loading.....
    By MarcJ in forum Installation, Configuration and Maintenance
    Replies: 3
    Last Post: 09-01-2012, 09:05 AM
  2. LDAP login works, but webaccess keeps loading
    By Wido in forum Installation and Configuration Archives
    Replies: 1
    Last Post: 28-11-2009, 04:39 PM
  3. Multi user calendar not loading in webaccess
    By conrad in forum Beta Feedback Archives
    Replies: 2
    Last Post: 26-02-2009, 03:29 PM
  4. Disable webaccess images from loading
    By Frido in forum WebAccess usage Archives
    Replies: 0
    Last Post: 03-12-2008, 01:15 PM
  5. Opening addressbook take very long
    By tisp in forum WebAccess usage Archives
    Replies: 7
    Last Post: 28-04-2008, 09:23 AM

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •