[prev in list] [next in list] [prev in thread] [next in thread] 

List:       linux-nfs
Subject:    Re: About pNFS installation process.
From:       Lev Solomonov <solo () tonian ! com>
Date:       2012-04-04 0:20:30
Message-ID: CAOdHTRDSrXorJuV0Sipy1dLKrZhoRW+3aV=peBmOEX-u0a6DmQ () mail ! gmail ! com
[Download RAW message or body]

sorry for the delay.

On Fri, Mar 23, 2012 at 19:21, Bruno Silva <bs@cin.ufpe.br> wrote:
> Fist of all, thanks for your replies.
>
> I still have a few questions:
>
> 1. What file system do you suggest? Why ext4 is not recommended?

i'm not aware of a single FS that will work perfectly out-of-the-box
with pNFS blocks layout on linux. in case of ext4/btrfs, there's tension
between the newer, advanced FS features and pNFS block layout underlying
FS requirements.

> 2. How know whether the pNFS is correctly set? Follows the blkmapd output:

IIRC neither client nor MDS nor DS emit blatantly bogus error messages,
so if you see any errors (e.g. 'failed' below) - that's a bad sign.

once you've cleared those, make sure that MDS exports pNFS, e.g.:
    grep pnfs /var/lib/nfs/etab
or similar shows your expected exports, and that client mounts those as
v4.1, e.g.:
    grep minorversion=1 /proc/mounts
or similar shows the expected mounts. then use the mounts on client
while sniffing the traffic, you'll want to see the file data move
around over iSCSI client<->DS rather than over NFS client<->MDS.

    <snip>
> *****    POINT 1    ******* I connected with four data servers using
> the command iscsiadm-m discovery-t-p SendTargets <IP DATE OF
> server>-l. But, note the output blkmapd "blkmapd: process_deviceinfo:
> 2 vols". I believe that should be listed four volumes, not two;

nope, the "2 vols" is just the single device info: simple+slice, and you
appear to have several of such devices. take a peek around GETDEVICEINFO
in RFC 5661 + 5663. regardless, DM barfed.

what export topology are you aiming for with those 4 volumes?

    <snip>
> Follows the output of command of "grep nfs /proc/self/mountstats"
>
> [bruno@fedora ~]$ grep nfs /proc/self/mountstats
> device sunrpc mounted on /var/lib/nfs/rpc_pipefs with fstype rpc_pipefs
> device 192.168.0.203:/ mounted on /home/bruno/shared with fstype nfs4
> statvers=1.0
>   nfsv4:  bm0=0xfdffbfff,bm1=0x40f9be3e,acl=0x3,sessions,pnfs=not configured
>   RPC iostats version: 1.0   p/v: 100003/4 (nfs)

the "pnfs=not configured" is bad news (no active pNFS layout driver),
you'll want that to say "pnfs=LAYOUT_BLOCK_VOLUME".

> My question is: How can i add other data servers in the structure and

did you manage to successfully export a single DS iSCSI LUN through MDS
over pNFS?

> how do I find out where the problem is?

DM is likely to have left something in /var/log/messages (or wherever)
on failed reloads. any 'device-mapper' entries there?

solo.
--
To unsubscribe from this list: send the line "unsubscribe linux-nfs" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
[prev in list] [next in list] [prev in thread] [next in thread]