[Beowulf] Suggestions to what DFS to use

[John Hanks]

Should have included this in my last message:

https://github.com/zfsonlinux/zfs/wiki/RHEL-%26-CentOS

One other aspect of ZFS I overlooked in my earlier messages is the built in
compression. At one point I backed up 460TB of data from our GPFS system
onto ~300TB of space on a ZFS system using gzip-9 compression on the target
filesystem, thereby gaining compression that was transparent to the users.
The benefits of ZFS are really too numerous to cover and the flexibility it
adds for managing storage open up whole new solution spaces to explore. For
me it is the go-to filesystem for the first layer on the disks.

jbh



On Tue, Feb 14, 2017 at 4:16 PM Tony Brian Albers <tba at kb.dk> wrote:

> On 2017-02-14 11:44, Jörg Saßmannshausen wrote:
> > Hi John,
> >
> > thanks for the very interesting and informative post.
> > I am looking into large storage space right now as well so this came
> really
> > timely for me! :-)
> >
> > One question: I have noticed you were using ZFS on Linux (CentOS 6.8).
> What
> > are you experiences with this? Does it work reliable? How did you
> configure the
> > file space?
> > From what I have read is the best way of setting up ZFS is to give ZFS
> direct
> > access to the discs and then install the ZFS 'raid5' or 'raid6' on top of
> > that. Is that what you do as well?
> >
> > You can contact me offline if you like.
> >
> > All the best from London
> >
> > Jörg
> >
> > On Tuesday 14 Feb 2017 10:31:00 John Hanks wrote:
> >> I can't compare it to Lustre currently, but in the theme of general, we
> >> have 4 major chunks of storage:
> >>
> >> 1. (~500 TB) DDN SFA12K running gridscaler (GPFS) but without GPFS
> clients
> >> on nodes, this is presented to the cluster through cNFS.
> >>
> >> 2. (~250 TB) SuperMicro 72 bay server. Running CentOS 6.8, ZFS presented
> >> via NFS
> >>
> >> 3. (~ 460 TB) SuperMicro 90 dbay JBOD fronted by a SuperMIcro 2u server
> >> with 2 x LSI 3008 SAS/SATA cards. Running CentOS 7.2, ZFS and BeeGFS
> >> 2015.xx. BeeGFS clients on all nodes.
> >>
> >> 4. (~ 12 TB) SuperMicro 48 bay NVMe server, running CentOS 7.2, ZFS
> >> presented via NFS
> >>
> >> Depending on your benchmark, 1, 2 or 3 may be faster. GPFS falls over
> >> wheezing under load. ZFS/NFS single server falls over wheezing under
> >> slightly less load. BeeGFS tends to fall over a bit more gracefully
> under
> >> load.  Number 4, NVMe doesn't care what you do, your load doesn't
> impress
> >> it at all, bring more.
> >>
> >> We move workloads around to whichever storage has free space and works
> best
> >> and put anything metadata or random I/O-ish that will fit onto the NVMe
> >> based storage.
> >>
> >> Now, in the theme of specific, why are we using BeeGFS and why are we
> >> currently planning to buy about 4 PB of supermicro to put behind it?
> When
> >> we asked about improving the performance of the DDN, one recommendation
> was
> >> to buy GPFS client licenses for all our nodes. The quoted price was
> about
> >> 100k more than we wound up spending on the 460 additional TB of
> Supermicro
> >> storage and BeeGFS, which performs as well or better. I fail to see the
> >> inherent value of DDN/GPFS that makes it worth that much of a premium in
> >> our environment. My personal opinion is that I'll take hardware over
> >> licenses any day of the week. My general grumpiness towards vendors
> isn't
> >> improved by the DDN looking suspiciously like a SuperMicro system when I
> >> pull the shiny cover off. Of course, YMMV certainly applies here. But
> >> there's also that incident where we had to do an offline fsck to clean
> up
> >> some corrupted GPFS foo and the mmfsck tool had an assertion error, not
> a
> >> warm fuzzy moment...
> >>
> >> Last example, we recently stood up a small test cluster built out of
> >> workstations and threw some old 2TB drives in every available slot, then
> >> used BeeGFS to glue them all together. Suddenly there is a 36 TB
> filesystem
> >> where before there was just old hardware. And as a bonus, it'll do
> >> sustained 2 GB/s for streaming large writes. It's worth a look.
> >>
> >> jbh
>
> That sounds very interesting, I'd like to hear more about that. How did
> you manage to use zfs on centos ?
>
> /tony
>
> --
> Best regards,
>
> Tony Albers
> Systems administrator, IT-development
> Royal Danish Library, Victor Albecks Vej 1, 8000 Aarhus C, Denmark.
> Tel: +45 2566 2383 <+45%2025%2066%2023%2083> / +45 8946 2316
> <+45%2089%2046%2023%2016>
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