topic Re: Quotas of Samba process in Operating System - OpenVMS

Quotas of Samba process

Antoniov. — Fri, 16 Sep 2005 07:59:08 GMT

I installed Samba and after some modification it's works almost fine.
The main limitation, at moment, is server too slow. I compared Advanced Server and Samba and discovered some quota differences.
For example, Advanced Server daemon run with buffered and direct I/O set to 32767.
It tryed run Samba daemon with same quotas but I can't do it.
The samba script is:
$ run/detached -
/input=samba_exe:nmbd_startup.com -
/output=samba_root:[var]nmbd_startup.log -
/uic=system
/process_name=NMBD -
sys$system:loginout.exe
In this case, NMBD use PQL_D* values.
If I add /authorize, process use value in SYSAUF.
So I have to select among some solution, but I'm not about best praticse.
I'm intrigued by your ideas.

TIA
Antonio Vigliotti

Re: Quotas of Samba process

Kris Clippeleyr — Fri, 16 Sep 2005 08:15:59 GMT

Antonio,
Just a warning, if /AUTHORIZE is specified then /UIC is ignored.
FWIW.
Kris (aka Qkcl)

Re: Quotas of Samba process

Antoniov. — Fri, 16 Sep 2005 08:24:48 GMT

Chris,
I start samba with SYSTEM accont, so it's no problem. However, I didn't remember this limitation.

Antonio Vigliotti

Re: Quotas of Samba process

Ian Miller. — Fri, 16 Sep 2005 08:42:50 GMT

I like to specify the quotas on the command line
RUN/AST_LIMIT=quota/BUFFER_LIMIT=quota
etc
/AUTHORIZE says use the quotas from the username (the process owner i.e. you)

Re: Quotas of Samba process

Antoniov. — Fri, 16 Sep 2005 09:35:01 GMT

Ian,
let me to be more specific.
I modified run command with /io_dir=/io_buf and other values but this didn't work.
Looked more carefully at code and saw inside nmbd_startup there is another run.
This is the code:
$ nmbd :== $samba_root:[bin]nmbd
$ opt = f$trnlnm("SAMBA_NMBD_OPTIONS")
$ nmbd "-d1" 'opt'
How you can see, nmbd receive some qualifier so i can't use run with usually qualifiers.
Again I can't give a value greater than my account (if /authorize). I want give DIO=32767 but I don't want modify SYSTEM account with this value.

Antonio Vigliotti

Re: Quotas of Samba process

Volker Halle — Fri, 16 Sep 2005 09:45:25 GMT

Antonio,

do you really believe that running NMBD with /IO_BUFFER or /IO_DIRECT=32767 will do any good ???

These quotas limit the number of CURRENTLY OUTSTANDING buffered or direct IOs for the process.

If NMBD would run against any of those limits, it will enter the MWAIT or MUTEX state. You could also have a look at the remaining BUFIO or DIRIO quota at any time using SHOW PROC/QUOTA/ID=. If those numbers get near ZERO, then that would need to get you worried...

Volker.

Re: Quotas of Samba process

David Jones_21 — Fri, 16 Sep 2005 09:52:18 GMT

Samba uses one process per client connection so I don't think you need high quotas the way you do for a multi-threaded daemon. The NMBD process is lanman browser function and isn't in the critical path. The advanced server uses special file system features to speed up access, I don't know if they are available for the Samba port.

Re: Quotas of Samba process

Bojan Nemec — Fri, 16 Sep 2005 09:53:08 GMT

Antonio,

The first run ($ run/detached...) creates a process where quotas are set, the second run ($ nmbd "-d1" 'opt') runs an image which takes quotas from the owner process.

Bojan

Re: Quotas of Samba process

Antoniov. — Fri, 16 Sep 2005 10:20:38 GMT

Volker,
BIO and DIO limit are just an example. I'm comparing pathwork server and samba daemon. For both values, Pathwork set value = 32767. You are right, these worth may be dangerous! However I need to supply big values for some quotas.

David,
thank you for your precious information. This difference can help me to understan why server runs slow.

Bojan,
I know it. Question is: how can I supply big quotas?

Just for your knowlege, setting prio=13 makes server more quicker but not enough for good use.

Antonio Vigliotti

Re: Quotas of Samba process

Bojan Nemec — Fri, 16 Sep 2005 10:34:59 GMT

Antonio,

David is right. NMBD is lanman browser. The real work is made by the service SMBD which is defined in TCPIP.
The process changes the owner to its VMS user. I dont know how is this done (a quick look to the sources was not succesful ;)

Bojan

Re: Quotas of Samba process

Volker Halle — Sat, 17 Sep 2005 01:32:57 GMT

Antonio,

The main limitation, at moment, is server too slow

Just arbitrarily changing process quotas would not make anything faster, if the process does not even deplete those quotas during operations.

I've played with SAMBA V2.2.8 recently and the file copy performance was acceptable when compared with FTP. Directory lookup and browsing large directories is another story...

Could you elaborate which operation you found to be 'too slow' ?

Volker.

Re: Quotas of Samba process

Antoniov. — Sat, 17 Sep 2005 09:54:00 GMT

Volker,
I'm playing with Samba 2.2.8 too and comparing with Advanced Server.
You are right about file copy but browsing, navigation and first open of share are not acceptable.
I'm also trying working office application (like word or excel) directly into shared directory.

Antonio Vigliotti

Re: Quotas of Samba process

Volker Halle — Sat, 17 Sep 2005 12:08:12 GMT

Antonio,

there are 2 mechanisms in SAMBA, which cause a performance penalty when handling/browsing/opening large directories:

- when accessing a file in any directory for the first time, SAMBA will fill it's directory cache, building a simple list of all file names within this directory. This list is used to later speed up wildcard accesses in that directory. Depending on the no. of files in the directory, building the file name list can take a while.

- when browsing a directory, SAMBA also fills it's stat (file) cache. As a Windows directory entry expects information like file access dates, file size etc. in addition to just the file name, this information needs to be obtained from the individual file headers in OpenVMS - again a somewhat IO intensive operation under OpenVMS.

Once the stat (file) cache is filled, things are getting a little better. But there are 2 problems with SAMBA V2.2.8 here:

* the stat cache handling of the directory tree is broken. This will cause the same file to be entered twice in different directories cache entries (once with /000000 included and once without). This causes the stat cache to not become effective starting the 3rd access to the directory. This is fixed in SAMBA V2.2.12.

* the no. of entries in the stat cache is limited to 16k files per directory. Once your directory grows beyond that no. of files, things get worse...

If you can keep the directory size small, SAMBA works quite well.

Volker.

Re: Quotas of Samba process

Peter Quodling — Sat, 17 Sep 2005 12:58:21 GMT

When you get it all done, it would be nice to see/hear a detailed how to. There isn't much info on SAMBA on VMS, and the only things that I have heard are a) that it is tricky to get going, and b) there hasn't been a new release for some time.

q

Re: Quotas of Samba process

Antoniov. — Mon, 19 Sep 2005 05:26:18 GMT

Volker,
your explanation is clear. I have to modify source of Samba to solve. You refer to V2.2.12 but I don't find that version of Samba on VMS. Where can I find it?

Antonio Vigliotti

Re: Quotas of Samba process

Volker Halle — Mon, 19 Sep 2005 05:39:19 GMT

Antonio,

I had received V2.2.12 from HP directly for a certain project. It seems to have once been made available by John M.

http://eisner.encompasserve.org/~malmberg/samba/

but it's not there anymore. Maybe you can ask John...

Volker.

Re: Quotas of Samba process

Antoniov. — Mon, 19 Sep 2005 12:04:41 GMT

Volker,
I write to John M. because I'm pleased to participate on development of new version of Samba.

Antonio Vigliotti

Re: Quotas of Samba process

Ian Miller. — Tue, 20 Sep 2005 03:34:55 GMT

I expect somewhere in hp someone is working on Samba V3 on VMS. Parhaps John knows more.

Re: Quotas of Samba process

Antoniov. — Tue, 20 Sep 2005 07:28:11 GMT

Ian,
me too.

Antonio Vigliotti

Re: Quotas of Samba process

Antoniov. — Tue, 20 Sep 2005 07:56:38 GMT

Ian,
off topic ...
I'm pleased to add some your link on new Italian OpenVMS comunity in section Friends of VMS.
If you like it send me
antoniov (at) shs-av.it
your favorite link

Antonio