samba - Sep 2011 - Increasing max stat cache

Hi ...,

We have a Lustre Storage with large directories. Many of these directories
contain thousands of files and we have hundreds of such directories.
Directory Listing on Lustre is very slow, due to the nature of most Parallel
File Systems design. It takes around 4 Secs (during non-peak hours) to list
a 2000 file directory. And during heavy load times, this goes upto 10-11
Secs.

Since all the users access the storage through a Samba gateway, we were
thinking whether Samba could help us solve this problem.

Here are my queries -
1. What is the finite upper limit of 'max_stat_cache' value? Not the
unlimited '0' option.
2. How much cache space does storing a typical stat consume? In other words
I would like to know how much memory will we require to cache obscene
amounts of Stat information?
3. Can we increase the max_stat_cache TTL? Since the files once created,
never ever change, I would like to set this to a very High value.
4. Is there anything else that I should look for, on increasing the
'max_stat_cache' value?

Regards,


Indivar Nair

Okay... I read about 'stat cache size' on this page -
http://www.samba.org/samba/docs/using_samba/ch11.html which says that it is
the number of entries.

But the man page (
http://www.samba.org/samba/docs/man/manpages-3/smb.conf.5.html) states that
'max stat cache size' is the number specified into kilobytes of space
provided for 'stat cache'.

So now my question is, how many kilobytes would it take to say store
something like 100,000 stat entries.
And what is the default and maximum TTL for these entries?

Regards,


Indivar Nair



On Mon, Sep 12, 2011 at 12:31 PM, Indivar Nair <indivar.nair at
techterra.in>wrote:
> Hi ...,
>
> We have a Lustre Storage with large directories. Many of these directories
> contain thousands of files and we have hundreds of such directories.
> Directory Listing on Lustre is very slow, due to the nature of most
> Parallel File Systems design. It takes around 4 Secs (during non-peak
hours)
> to list a 2000 file directory. And during heavy load times, this goes upto
> 10-11 Secs.
>
> Since all the users access the storage through a Samba gateway, we were
> thinking whether Samba could help us solve this problem.
>
> Here are my queries -
> 1. What is the finite upper limit of 'max_stat_cache' value? Not
the
> unlimited '0' option.
> 2. How much cache space does storing a typical stat consume? In other words
> I would like to know how much memory will we require to cache obscene
> amounts of Stat information?
> 3. Can we increase the max_stat_cache TTL? Since the files once created,
> never ever change, I would like to set this to a very High value.
> 4. Is there anything else that I should look for, on increasing the
> 'max_stat_cache' value?
>
> Regards,
>
>
> Indivar Nair
>
>
>