From mboxrd@z Thu Jan 1 00:00:00 1970 From: Yuri Csapo Subject: Re: re-export NFS mounted disk to be NFS mounted? Date: Mon, 23 Mar 2009 11:23:52 -0600 Message-ID: <49C7C5A8.206@mines.edu> References: <2535BDE3-66FC-49AB-BD55-D663368370F2@hhmi.umbc.edu> <49C7B5AF.7020107@mines.edu> Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: Sender: linux-admin-owner@vger.kernel.org List-ID: Content-Type: text/plain; charset="us-ascii"; format="flowed" To: Yu Chen Cc: linux-admin , Server MacOSX Well, a lot of it depends on the hardware you have, but re-exporting is really not a good idea no matter which protocol you use. Unless the cluster is a computational cluster which only needs to read/write disks sporadically, I'd strongly suggest you give it its own disk space, directly attached to the head node (or use a SAN, but that's beside the scope here I think). We have a number of clusters here and there are 2 different solutions we use (that I'm aware of): - For the big supercomputer we use a SAN which all nodes can see with Lustre as a filesystem. You can see hardware details here: http://geco.mines.edu/hardware.shtml - For small clusters (typically 10-node) we use disks directly attached to the head and NFS-exported to the nodes. This is just one hop of NFS so it's not that bad; still we work around it (after a fashion) by having local disks on each node that can be used as a temporary, node-specific scratch area. Hope this helps... Yuri Yu Chen wrote: > Thanks Yuri, > > Other than NFS, what else can I do, I heard a lot about NFS's > performance, but I just don't know an alternative yet (AFP doesn't work > that well on a server as what I read from mail lists, and from trying). > > Guess I will go to local disk solution. > > CY > > On Mar 23, 2009, at 12:15 PM, Yuri Csapo wrote: > >> AFAIK that is not possible on Linux with the stock kernel nfs server. >> It *should* be possible with the userspace server, but I'm not sure >> it's supported. Maybe someone who has actually done it (as opposed to >> playing with it) should comment. >> >> OTOH it doesn't seem like a good idea anyway... NFS's performance is >> really bad and what you're doing will multiply bad x 2. I know >> sometimes you need to work with what you have but if your cluster is >> in any way I/O sensitive you should think about getting some local >> disk space for it, at least. >> >> Yu Chen wrote: >>> Hello, >>> I have a cluster, the disk space is on a Xserver, it's NFS exported, >>> and mounted on the cluster's head node without problem (mounted on >>> /mnt/nfs), then I exported the "/mnt/nfs" directory, then tried to >>> mount it on the nodes in the cluster (mount -t nfs headnode:/mnt/nfs >>> /mnt/tmp), it gave error: mount ... failed, reason given by server: >>> Permission denied. >>> my Xserver nfs exports entry has this: /Volumes/DataRAID -alldirs >>> -maproot=nobody -sec=sys -network my.headnode.network -mask >>> 255.255.255.0 >>> my headnode mounted /Volumes/DataRAID on /mnt/nfs then exported as >>> nfs exports entry: >>> /mnt/nfs 10.0.0.0/255.255.255.0(rw,sync) >>> Anybody has any suggestions? >>> Thanks in advance. >>> CY >>> -- >>> To unsubscribe from this list: send the line "unsubscribe >>> linux-admin" in >>> the body of a message to majordomo@vger.kernel.org >>> More majordomo info at http://vger.kernel.org/majordomo-info.html >> >> -- >> Yuri Csapo >> Academic Computing & Networking >> Colorado School of Mines >> CT-256 >> Phone: (303) 273-3503 >> Fax: (303) 273-3475 >> Email: ycsapo@mines.edu >> >> Please use the following link to open a service request: >> http://helpdesk.mines.edu >> =========================================== >> With a PC, I always felt limited >> by the software available. >> On Unix, I am limited only by my knowledge. >> --Peter J. Schoenster >> -- Yuri Csapo Academic Computing & Networking Colorado School of Mines CT-256 Phone: (303) 273-3503 Fax: (303) 273-3475 Email: ycsapo@mines.edu Please use the following link to open a service request: http://helpdesk.mines.edu =========================================== With a PC, I always felt limited by the software available. On Unix, I am limited only by my knowledge. --Peter J. Schoenster