Celerra is the name of the NAS product from EMC. It consists of from 1 to 14 data movers which are each kind of like a small filer without DataONTAP and WAFL. The entire collection of data movers is controlled from a "control station" located in the same cabinet as the data movers. Each data mover is connected to the Symmetrix storage subsystem via direct-attached SCSI interfaces and connected to the network via network interfaces.
There is no such thing as Celerra processing power in and of itself. Data movers may be configured within a Celerra for cluster failover, but the failover occurs to a hot standby data mover that is not otherwise being used to serve data. More than one data mover can access the same file system but only one of them has RW acess to that file system. The others would have RO access. In any event each data mover has only one volume (or file system) associated with it. There is no VIF support for NIC failover. There is no fast etherchannel. Gigabit ethernet and ATM are brand new technologies to EMC. Netapp has had both for over two years. There are no Snapshots on a Celerra. For multiprotocol support they use a version of Sambs that runs on top of their UxFS file system.
The EMC concept of scalability is also a bit self serving. The claim that they can scale to 9TB within a box sounds impressive but actually adds up to very little. It's easier to deploy 9 1TB filers than a single 9TB Symmetrix. Also, with netapp you can start at 1 or two and grow to 9 as you need. You don't have to buy this huge hulking giant of a storage subsystem and then grow within it. You can actually grow your storage as you need it. Also, when you hit the 9TB limit on a Sym you then have to buy another (plus another Celerra and more data movers to deploy it with.
I hope I don't sound too negative, but I know both products fairly well and I think filers are a far superior solution. But then again I work for Netapp don't I :-) Celerra usually only appeals to folks who have already invested huge sums of money in EMC Symmetrix boxes and now need a NAS solution that works with them to help justify the purchase of them in the first place. If you don't already have a Symmetrix the solution becomes quite expensive.
From: owner-dl-toasters@netapp.com [mailto:owner-dl-toasters@netapp.com]On Behalf Of G D Geen Sent: Friday, April 07, 2000 12:37 PM To: toasters@mathworks. com Subject: Re: EMC Celerra vs NetApp Filer
Brian,
We have seen the same thing, we are running out of CPU cycles and we continue to add capacity to our LSF pool. I am very familiar with the NetApp product but have no experience with the EMC but we are talking to them in a lot.
My understanding that, yes you could add Celerra processing power to the front end, but are you not still limited by the capacity of the data movers on the back end? One may point several Celerra processors to a file system but there is still only a single data mover to a volume. Please help me if I misunderstand the EMC configuration.
-gdg
Brian Tao wrote:
On Mon, 3 Apr 2000, Bruce Sterling Woodcock wrote:
What do you mean by this? Not enough total storage?
Might be a CPU limitation. Every single one of my Netapps willrun out of CPU cycles long before they run out of disk. A clustered pair of the F740's routinely burst over 10000 NFS ops/sec each, but they only need a couple shelves of 18GB drives between them. With an EMC Celerra, you can keep the same pool of drives, but plug in more front-end processors to soak up the NFS load. I believe they support up to 14 of those, sharing the same array of drives.
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