[Beowulf] Lustre Upgrades

Jörg Saßmannshausen sassy-work at sassy.formativ.net
Tue Jul 24 01:52:44 PDT 2018


Hi Paul,

with a file system being 93% full, in my humble opinion it would make sense to 
increase the underlying hardware capacity as well. The reasoning behind it is 
that usually over time there will be more data on any given file system and 
thus if there is already a downtime, I would increase the size of it as well. 
I rather have a bit of a longer down time and then I got a new version of 
Luster (of which I know little about) and more capacity which will last for 
longer than only upgrading Luster and then run out of disc capacity a bit 
later. 
It also means that in your case you could simply install the new system, test 
it, and then migrate the data over. Depending how it is set up you even could 
do that at stages. 
As you mentioned 3 different Luster servers, you could for example start with 
the biggest one and use new hardware here. The freed capacity of the now 
obsolete hardware could for example being utilized for the other systems. 
Of course, I don't know your hardware etc. 

Just some ideas from a hot London 8-)

Jörg


Am Montag, 23. Juli 2018, 14:11:40 BST schrieb Paul Edmon:
> Yeah we've pinged Intel/Whamcloud to find out upgrade paths as we wanted
> to know what the recommended procedure is.
> 
> Sure. So we have 3 systems that we want to upgrade 1 that is a PB and 2
> that are 5 PB each.  I will just give you a description of one and
> assume that everything would scale linearly with size. They all have the
> same hardware.
> 
> The head nodes are Dell R620's while the shelves are M3420 (mds) and
> M3260 (oss).  The MDT is 2.2T with 466G used and 268M inodes used.  Each
> OST is 30T with each OSS hosting 6.  The filesystem itself is 93% full.
> 
> -Paul Edmon-
> 
> On 07/23/2018 01:58 PM, Jeff Johnson wrote:
> > Paul,
> > 
> > How big are your ldiskfs volumes? What type of underlying hardware are
> > they? Running e2fsck (ldiskfs aware) is wise and can be done in
> > parallel. It could be within a couple of days, the time all depends on
> > the size and underlying hardware.
> > 
> > Going from 2.5.34 to 2.10.4 is a significant jump. I would be sure
> > there isn't a step upgrade advised. I know there has been step
> > upgrades in the past, not sure about going to/from these two versions.
> > 
> > --Jeff
> > 
> > On Mon, Jul 23, 2018 at 10:34 AM, Paul Edmon <pedmon at cfa.harvard.edu
> > 
> > <mailto:pedmon at cfa.harvard.edu>> wrote:
> >     Yeah we've found out firsthand that its problematic as we have
> >     been seeing issues :).  Hence the urge to upgrade.
> >     
> >     We've begun exploring this but we wanted to reach out to other
> >     people who may have gone through the same thing to get their
> >     thoughts.  We also need to figure out how significant an outage
> >     this will be.  As if it takes a day or two of full outage to do
> >     the upgrade that is more acceptable than a week.  We also wanted
> >     to know if people had experienced data loss/corruption in the
> >     process and any other kinks.
> >     
> >     We were planning on playing around on VM's to test the upgrade
> >     path before committing to upgrading our larger systems.  One of
> >     the questions we had though was if we needed to run e2fsck
> >     before/after the upgrade as that could add significant time to the
> >     outage for that to complete.
> >     
> >     -Paul Edmon-
> >     
> >     On 07/23/2018 01:18 PM, Jeff Johnson wrote:
> >>     You're running 2.10.4 clients against 2.5.34 servers? I believe
> >>     there are notable lnet attrs that don't exist in 2.5.34. Maybe a
> >>     Whamcloud wiz might chime in but I think that version mismatch
> >>     might be problematic.
> >>     
> >>     You can do a testbed upgrade to test taking a ldiskfs volume from
> >>     2.5.34 to 2.10.4, just to be conservative.
> >>     
> >>     --Jeff
> >>     
> >>     
> >>     On Mon, Jul 23, 2018 at 10:05 AM, Paul Edmon
> >>     
> >>     <pedmon at cfa.harvard.edu <mailto:pedmon at cfa.harvard.edu>> wrote:
> >>         My apologies I meant 2.5.34 not 2.6.34. We'd like to get up
> >>         to 2.10.4 which is what our clients are running.  Recently we
> >>         upgraded our cluster to CentOS7 which necessitated the client
> >>         upgrade.  Our storage servers though stayed behind on 2.5.34.
> >>         
> >>         -Paul Edmon-
> >>         
> >>         On 07/23/2018 01:00 PM, Jeff Johnson wrote:
> >>>         Paul,
> >>>         
> >>>         2.6.34 is a kernel version. What version of Lustre are you
> >>>         at now? Some updates are easier than others.
> >>>         
> >>>         --Jeff
> >>>         
> >>>         On Mon, Jul 23, 2018 at 8:59 AM, Paul Edmon
> >>>         
> >>>         <pedmon at cfa.harvard.edu <mailto:pedmon at cfa.harvard.edu>> wrote:
> >>>             We have some old large scale Lustre installs that are
> >>>             running 2.6.34 and we want to get these up to the latest
> >>>             version of Lustre.  I was curious if people in this
> >>>             group have any experience with doing this and if they
> >>>             could share them.  How do you handle upgrades like
> >>>             this?  How much time does it take?  What are the
> >>>             pitfalls?  How do you manage it with minimal customer
> >>>             interruption? Should we just write off upgrading and
> >>>             stand up new servers that are on the correct version (in
> >>>             which case we need to transfer the several PB's worth of
> >>>             data over to the new system)?
> >>>             
> >>>             Thanks for your wisdom.
> >>>             
> >>>             -Paul Edmon-
> >>>             
> >>>             _______________________________________________
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> >>>         
> >>>         jeff.johnson at aeoncomputing.com
> >>>         <mailto:jeff.johnson at aeoncomputing.com>
> >>>         www.aeoncomputing.com <http://www.aeoncomputing.com>
> >>>         t: 858-412-3810 x1001   f: 858-412-3845
> >>>         m: 619-204-9061
> >>>         
> >>>         4170 Morena Boulevard, Suite C - San Diego, CA 92117
> >>>         
> >>>         High-Performance Computing / Lustre Filesystems / Scale-out
> >>>         Storage
> >>>         
> >>>         
> >>>         _______________________________________________
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> >>         
> >>         _______________________________________________
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> >>     
> >>     jeff.johnson at aeoncomputing.com
> >>     <mailto:jeff.johnson at aeoncomputing.com>
> >>     www.aeoncomputing.com <http://www.aeoncomputing.com>
> >>     t: 858-412-3810 x1001   f: 858-412-3845
> >>     m: 619-204-9061
> >>     
> >>     4170 Morena Boulevard, Suite C - San Diego, CA 92117
> >>     
> >>     High-Performance Computing / Lustre Filesystems / Scale-out Storage
> >>     
> >>     
> >>     _______________________________________________
> >>     Beowulf mailing list,Beowulf at beowulf.org <mailto:Beowulf at beowulf.org>
> >>      sponsored by Penguin Computing To change your subscription (digest
> >>     mode or unsubscribe)
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> >     
> >     _______________________________________________
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> > 
> > jeff.johnson at aeoncomputing.com <mailto:jeff.johnson at aeoncomputing.com>
> > www.aeoncomputing.com <http://www.aeoncomputing.com>
> > t: 858-412-3810 x1001   f: 858-412-3845
> > m: 619-204-9061
> > 
> > 4170 Morena Boulevard, Suite C - San Diego, CA 92117
> > 
> > High-Performance Computing / Lustre Filesystems / Scale-out Storage
> > 
> > 
> > _______________________________________________
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