comparison between NetApp Filer and EMC Celerra

comparison between NetApp Filer and EMC Celerra

Post by virtualjac » Sun, 10 Jun 2007 17:37:58

Does anyone have (relatively recent) experience with both a
NetApp NAS & EMC Celerra? If so, I'ld appreciate any comments
that you might have.

Our management is looking into replacing our NAS3020 with a
Celerra NS40G.

Thanks in advance!


Jack Stewart
Emal: jack dash nospam at

comparison between NetApp Filer and EMC Celerra

Post by Rob Tur » Mon, 11 Jun 2007 02:11:11

What is your management hoping to gain from this switch? The 3020 is still a
current machine, does it fail to perform it's duties in some way?



comparison between NetApp Filer and EMC Celerra

Post by virtualjac » Mon, 11 Jun 2007 03:11:53

Their main motivation is that they are hoping to leverage the Clarion
and our considerably larger relationship with Dell/EMC.

Unfortunately EMC doesn't seem to be willing to give us any type of
demo Celerra unit
at this time so my analysis is strictly based on their documentation
and answers from
the Sales Engineers (who frankly don't seem to understand the product
very well).

So real world experience of the Celerra is what I'm most looking for.
People who have
migrated from one to another (either way) would be fabulous, but even
plain real world
experience of the Celerra would help (EMC also hasn't located a decent
Customer reference

The 3020 is working fine although ndmpd backups are not going as fast
as we would like -
it is probably more of an issue with the backup system - although I'm
beginning to think
that my RAID group & Aggregate configuration is sub-optimal.


P.S. Sorry for the change in headers, my Palm newsreader foobar'ed
this article.

P.S. Based on what I've read so far, the Celerra has a more feature
rich CIFS implementation.
The spare "head/cpu board" is a nice feature as are the disjoint CIFS/
Unix ACL's. On the other
hand, the Celerra seems more wasteful of disk allocation and more
difficult to manage in our
environment which is script based.

comparison between NetApp Filer and EMC Celerra

Post by Raju Mahal » Tue, 12 Jun 2007 00:06:55

May I ask, which backup server are you using ?
ndmp is purely file base backup which uses unix dump. NetApp is best
design for reading so if data layout is well placed then read
shouldn't be the issue. Check with your backup server performance ?
Mainly factors those afftect the ndmp performance are : more no. of
file in the volume, average file size is very less, or if there are
file level fragmentation etc. So you check in this direction.
One another thing which may be the reason is usage of filer during
ndmp remains good because ndmp is low priority job compared to CIFS/
NFS data serving. So you check that also.

- Raju

comparison between NetApp Filer and EMC Celerra

Post by Faeanda » Tue, 12 Jun 2007 07:31:23

n Sat, 09 Jun 2007 11:11:53 -0700, virtualjack
< XXXX@XXXXX.COM > wrote:

When a vendor is not willing to let you try before you buy that should
be a warning sign. And when the SE does not understand what it is
he's supposed to support, well that's another warning sign.

I would wager that's because they do not have one for their NAS. I ma
a NetApp biggot when it comes to traditional NAS so keep that in mind
as I spout off about both.

I do not have any direct EMC experience so all my info on that end is
purely anecdotal. But I do talk with other shops and the few that
have had EMC NAS got rid of it at the earliest opportunity, usually
following some major outage.

I spoke to one shop where they removed all the EMC NAS blades after
they took a 6 hour downtime for EMC to perform a DART upgrade. That
was it, no hardware swaps, no data migration, nothing. Just an OS
upgrade. That happened twice so it wasn;t isolated. They got rid of
it within a month after the second one. I don't recall what they
moved to so it may not have been NetApp.

If you go looking for shops that are heavy users of NAS it is my
opinion you will not find a single one that uses EMC. I'm certain
you'll find some shops where they have alot of EMC SAN and need NAS
for one or two things, so they drop in a Celerra and it "works
enough". But any real users will not touch that stuff.

Backups on a filer simply use dump, so nothing magic there. Many
times when backups are problematic it's because there are a ton of
files. There is nothing any file system will do to fix that for a
dump-type backup. Snapshots, block level backups, etc all mask the
real issue. But for a full file system dump you're just hosed if
that's your problem.
Post your aggregate layout and we can give you pointers if it's truly

Changing out something that is "working fine" is usually a sign of bad
things to come.

Unless EMC deviated from the CIFS spec I don't see how they can have a
more rich feature set than NetApp. I'm pretty sure the only way to
get more CIFS features than NetApp is to use Windows NAS. Which, btw,
I would recommend before I recommend the Celerra.

I assume the 3020 is not clustered? With 12 clusters I have 8 that
had 100% availability last year. 2 of those required RAM swaps, the
rest were OS bugs causing panics. But because of clustering there was
no impact to access.


comparison between NetApp Filer and EMC Celerra

Post by Maxim S. S » Tue, 12 Jun 2007 08:41:39

> Backups on a filer simply use dump, so nothing magic there. Many

In Windows, the block level backup speed is NOT related to number of files on
the volume.

The reason is that in Windows, such backup has no need to enumerate the files.
There is FSCTL_GET_VOLUME_BITMAP call which allows to enumerate the _busy
blocks on the volume_, regardless of to what file do they belong.

When I saw Linux last time (early 2000ies), it only had FIBMAP IOCTL which is
the same as Windows's FSCTL_GET_RETRIEVAL_POINTERS - get the disk block number
for a file offset. As about FSCTL_GET_VOLUME_BITMAP - it was absent in Linux.

Maxim Shatskih, Windows DDK MVP
StorageCraft Corporation

comparison between NetApp Filer and EMC Celerra

Post by Nik Simpso » Tue, 12 Jun 2007 09:34:04

Have they considered one of the Netapp V series heads, you could use
that to provide NAS services (as wells as iSCSI & FC target services) in
front of the Clariion storage. At least try getting an eval from Netapp,
I bet if you're EMC salesman new that you had the Netapp box in for test
he'd be much more willing to let you get hands on a Celerra. Right now I
expect he thinks he's in the driving seat and you'll end up swallowing
the Celerra if he just hangs tough.

Nik Simpson

comparison between NetApp Filer and EMC Celerra

Post by Faeanda » Tue, 12 Jun 2007 14:53:33

On Mon, 11 Jun 2007 03:41:39 +0400, "Maxim S. Shatskih"

I was not referring to block level backups. Snapshot to tape from
NetApp for a volume level backup is lightning fast and will push tape
to it's max instantly, and keep it there.

But when you want to backup *files* you have to enumerate and match
inodes and files to blocks. That is where it matters not at all what
file system you have, you are borked.


comparison between NetApp Filer and EMC Celerra

Post by JS » Wed, 13 Jun 2007 23:25:27

Thanks to everyone for their feedback.

It is somewhat telling that nobody has jumped in (yet) and said that "the
Celerra has been Great for us!".

Our backup situation vastly improved once we power cycled the backup control
host (a Sun box running Backup Express from Sync Sort) and the Jukebox ( a
Spectra Logic Gator). Bizarre. One of our back up sets contains lots of little
files so it will always be slow (it is Maildir which will be migrating to a
SAN real soon now ...). Snapshot to tape would give us great performance but
it only allows for full file system restores. It seems to be that near line
storage/virtual tapes might be a good upgrade but it is pricey.

I hate to defend a box that that we have never had but based on their dog &
pony show, the out of the box EMC's CIFS shares of filesystems are virtual so
you can have one IP address per filesystem. This feature does not extend to
NFS (IP's are for all shares). The NetApp doesn't do this unless you purchase
their virtual server license. This kind of strikes me as one of those
"optional" features that get bundled with new car no matter what. The disjoint
ACL's may or may not be beneficial depending on your point of view.

I wish we could afford a 3020 cluster - that is one of the reasons we are
considering a Celerra. On the other hand, we have never had a hardware failure
on any of our NetApps (other than a typical disk failure) as far back as our
group has been running NetApps (at least 1999).

I would chose a NAS over a Microsoft server for CIFS shares any day,
especially dual purpose home directories. Microsoft servers have a habit of
issues after their frequent patches and running a Samba server is no joy.

Again, thanks to everyone for their help.


comparison between NetApp Filer and EMC Celerra

Post by Anthony » Thu, 14 Jun 2007 09:53:49


Here are some objective high level comparisons that you may want to look
into. I have extensive experience with the Celerra and I can assure you
there are many large businesses using these units exclusively with
minimal issues. Same goes for NetApp, recent versions of both products
work very well but there are some notable differences. I'm an NACE and
have implemented both solutions for a number of clients both small and
large and directly managed Celerra in a medium sized organization (100TB
managed) a couple years ago. Here's what I've seen:

Also first, let me say that I enjoy working with both products, and
they're both top notch, it's just a matter of understanding caveats and
how those caveats impact your functional requirements. Usually they
dont, and it comes down to cost/preference/politics/relationships, or
some other non-technical reason.

I've seen and heard horror stories from both sides. If you have a
proper configuration both products should perform as advertised. I've
been in clients that ripped out NetApp and went with EMC, and vice
versa. The Reasons are numerous.

Back-end Disk management:
NetApp provides a very 'direct' way of managing disks which belong to
the system. It's very easy to ensure data is kept on separate spindles.
It's also very easy to configure any type of aggregate/raid group
configuration you'd like (only raid4 or raidDP of course..). The
celerra has its own volume manager called AVM. It's slightly more
difficult to force your data onto certain spindles, and only certain
layouts in regards to RAID group configuration per shelf are permitted.
You can still place data discreetly, but make sure to understand AVM
and it's implications, you also have the option of performing a manual
volume config. Functionally both work very well, but a couple more
caveats on the EMC side. If you're using this for CIFS only, you can
typically let AVM manage all of the disks from the start, and it will
automatically balance IO across the backend disks. Just make sure the
implementation engineer knows this and explains it to you well.

Interface and management:
The Celerra in my opinion has a more functional management interface,
both GUI and CLI. I think this is what you were alluding to, not
necessarily CIFS features. Theres one (or two for redundancy) dedicated
1U management server called the control station. This is essentailly
runs a customized linux distro which contains a set of applications
which manage the data movers (the actual NAS hardware). It also runs a
webserver which presents the GUI interface which is JAVA based. The GUI
has much more performance analysis features that the NetApp side, and
looks a lot better (if that matters). Also, since the control station
is a linux box, and you do have root access to it, and you actually get
a real fully functional bash shell. It'll may even be easier to manage
via a script based management infrastructure.

CIFS/NFS (file access):
Couple things worth noting off the top of my head. The Celerra does
offer more of what I'd call, configuration flexibility. basically, it
essentially allows you to perform the equivalent of what the vFiler
option would do out of the box. Just an example, you can create
multiple virtual CIFS servers and join them to separate domains. In
fact to present data via CIFS you need to create one