Re: 32 group limit

[Anand Avati <avati@xxxxxxxxxxx>]

David,

http://review.gluster.org/7501 will "fix" the problem (in 3.5.x when it gets backported), by providing a workaround solution where you (the admin) will have to set up user accounts on the server side which are capable of resolving the list of groupIDs for a user through getpwuid() call, and it is the admin's responsibility to keep these credentials synchronized (either using a centralized directory/ldap service or manually/scripting.)

In the last email I was referring to another approach where such an "extra setup" is not necessary and the gluster native client and server can fetch all the required groupIDs without any outside help.

There are benefits and problems with both approaches.

HTH

On Mon, May 19, 2014 at 11:57 AM, David F. Robinson <david.robinson@xxxxxxxxxxxxx> wrote:

Avati,

 

I am slightly confused.  Should we be able to utilize 93-groups with the current (3.5.0-2) release of gluster and fuse?  Or, are we stuck with 32-groups until the fixes are released in the next version?

It wasn't clear if the fixes were to take you up to the 93-group limit or beyond it...

 

David

 

 

------ Original Message ------

From: "Anand Avati" <avati@xxxxxxxxxxx>

To: "Niels de Vos" <ndevos@xxxxxxxxxx>

Cc: "gluster-users" <gluster-users@xxxxxxxxxxx>

Sent: 5/19/2014 2:50:54 PM

Subject: Re: 32 group limit

 

On Mon, May 19, 2014 at 8:39 AM, Niels de Vos <ndevos@xxxxxxxxxx> wrote:

The 32 limit you are hitting is caused by FUSE. The Linux kernel module
provides the groups of the process that accesses the FUSE-mountpoint
through /proc/$PID/status (line starting with 'Groups:'). The kernel
does not pass more groups than 32, this limit is hardcoded in the FUSE
kernel module.

Minor nit - 32 groupid limit is independent of FUSE. It is just the limited number of groupIDs the kernel exposes through proc. FUSE filesystems's only option is to use this sub-optimal interface to get group IDs. It is not unreasonable to actually implement a new reverse call in FUSE over /dev/fuse to resolve group-ids of a given request/process. Even then, the 400byte RPC limit of 93 would apply (we could at some point in the future move away from RPC)

Avati

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