Webmail - considerations...
We are going to develop web-mail system, that's capable of handling relatively high loads. I know, there are many open source web-mail systems , but they doesn't satisfy me. Almost every falls into one of two cateogries: php based, using imap; perl cgi based, using IMAP or direct filesystem access... I'd like someone experienced with such systems help me with the following: 1. Almost every available webmail system uses the following way of handling (rreceiving, in this example) attachements: load the whole message body from IMAP server or message file, decode it and send to the client. The _whole_ attachement gets loaded into server's RAM. Isn't it waste of resources/ killing the server ? I think it should read/decode/send the attachement on a line-by-line (or part-by-part generaly) manner. Am I right ? 2. Which one is better - accessing maildirs directly, or using IMAP ? I can see that IMAP seems to be more scalable / universal... Maildirs probably can be much faster to work with directly, but probably less secure... Any other pros/contras ? 3. I'm going to develop the front-end using Apache::ASP or php, not decided yet, and access the mails through the middle-tier daemon. The question is - is it a good way to use persistent IMAP connections ? If so, there will be no overhead of authentication on every operation, but there can be many open IMAP connections to the local imap server (probably Courier-IMAP) at the same time. Which strategy is better ? 4. Are there any libraries similar to c-client, maybe some C++ ones ? 5. Does c-client library allow to retrieve the message body (attachements) partialy (see 1) ? I've seen some /tmp access in its source code - does it dowload whole message to /tmp ? Hmm, that's all for now... TIA -=Czaj-nick=- -- To UNSUBSCRIBE, email to [EMAIL PROTECTED] with a subject of unsubscribe. Trouble? Contact [EMAIL PROTECTED]
Re: Finding the Bottleneck
On Sun, Jun 10, 2001 at 02:04:36AM +0800, Jason Lim wrote: I'm not exactly sure how the Linux kernel would handle this. Right now, the swap is untouched. If the server needed more ram, wouldn't it be swapping something... anything? I mean, it currently has 0kb in swap, and still has free memory. Here is a recent top: 101 processes: 97 sleeping, 3 running, 1 zombie, 0 stopped CPU states: 9.4% user, 14.0% system, 0.5% nice, 76.1% idle Mem:128236K total, 125492K used, 2744K free,69528K buffers Swap: 289160K total,0K used, 289160K free,10320K cached Remember that adding RAM means larger buffers/cache, and so faster IO. Only 3 MB free memory means that Linux would really like more RAM for larger buffers. Marcin -- Marcin Owsiany [EMAIL PROTECTED] http://student.uci.agh.edu.pl/~porridge/ GnuPG: 1024D/60F41216 FE67 DA2D 0ACA FC5E 3F75 D6F6 3A0D 8AA0 60F4 1216 -- To UNSUBSCRIBE, email to [EMAIL PROTECTED] with a subject of unsubscribe. Trouble? Contact [EMAIL PROTECTED]
Webmail - considerations...
We are going to develop web-mail system, that's capable of handling relatively high loads. I know, there are many open source web-mail systems , but they doesn't satisfy me. Almost every falls into one of two cateogries: php based, using imap; perl cgi based, using IMAP or direct filesystem access... I'd like someone experienced with such systems help me with the following: 1. Almost every available webmail system uses the following way of handling (rreceiving, in this example) attachements: load the whole message body from IMAP server or message file, decode it and send to the client. The _whole_ attachement gets loaded into server's RAM. Isn't it waste of resources/ killing the server ? I think it should read/decode/send the attachement on a line-by-line (or part-by-part generaly) manner. Am I right ? 2. Which one is better - accessing maildirs directly, or using IMAP ? I can see that IMAP seems to be more scalable / universal... Maildirs probably can be much faster to work with directly, but probably less secure... Any other pros/contras ? 3. I'm going to develop the front-end using Apache::ASP or php, not decided yet, and access the mails through the middle-tier daemon. The question is - is it a good way to use persistent IMAP connections ? If so, there will be no overhead of authentication on every operation, but there can be many open IMAP connections to the local imap server (probably Courier-IMAP) at the same time. Which strategy is better ? 4. Are there any libraries similar to c-client, maybe some C++ ones ? 5. Does c-client library allow to retrieve the message body (attachements) partialy (see 1) ? I've seen some /tmp access in its source code - does it dowload whole message to /tmp ? Hmm, that's all for now... TIA -=Czaj-nick=-
Perl 5.6 Potato
Is it possible to run perl 5.6 iwth Potato without upgrading 50% of the system ? I've tried to build debs from Woody, but they fails during ndbm tests... -=Czaj-nick=-
Re: Finding the Bottleneck
On Sun, Jun 10, 2001 at 02:04:36AM +0800, Jason Lim wrote: I'm not exactly sure how the Linux kernel would handle this. Right now, the swap is untouched. If the server needed more ram, wouldn't it be swapping something... anything? I mean, it currently has 0kb in swap, and still has free memory. Here is a recent top: 101 processes: 97 sleeping, 3 running, 1 zombie, 0 stopped CPU states: 9.4% user, 14.0% system, 0.5% nice, 76.1% idle Mem:128236K total, 125492K used, 2744K free,69528K buffers Swap: 289160K total,0K used, 289160K free,10320K cached Remember that adding RAM means larger buffers/cache, and so faster IO. Only 3 MB free memory means that Linux would really like more RAM for larger buffers. Marcin -- Marcin Owsiany [EMAIL PROTECTED] http://student.uci.agh.edu.pl/~porridge/ GnuPG: 1024D/60F41216 FE67 DA2D 0ACA FC5E 3F75 D6F6 3A0D 8AA0 60F4 1216
