Good day all,

I would like to respond to this topic. Though we have no EMC in our design environment, EMC has made several trips to Texas Instruments to inform us on their product line. Back in June of 2001, EMC reported to us on the capabilities of the EMC IP4700 and please let me know if they have made updates to the sales pitch since then.

The IP4700 is said to perform 50K NFS ops/sec. Now this is good but one must note that this is using four channels which computes to 12.5K NFS ops/sec per channel. That is less performance per channel than a single F720 NetApp filer. Along the same lines, EMC rated throughput as 340MB/sec. Again this is using all four channels.

As for scallability the new NetApp F840 scales just as well -- 12TB today and 18TB in a new DOT release due this year. This is roughly equal to that of the IP4700 as stated in June of 2001.

The IP4700 supports RAID 0, 1, 0+1, and 5 whereas the NetApp is RAID4 and WAFL file system. I will let you make the call there but I am happy with the performance of the WAFL system and RAID 4 of the NetApp.

The storage processor of the IP4700 consisted of two PIII Celerons. This may be upgraded by now.

As for disk usage, I found this to be an interesting concept but I will let you decide which is better. On the EMC all disks in a RAID group must be the same size, no different from NetApp. Upon disk failure, however, the EMC grabs the first available disk. Now if you have multiple size disks in your system, the spare disk *must* be of the largest size you have on your system. On the NetApp, the filer will grab the smallest spare disk of equal or larger size of the one that failed. Thus, if you have 36GB and 72GB drives on your NetApp and a 36GB drive fails, the NetApp will try to find a 36GB spare. If one is not found then a larger spare will be resized and used as a spare.

Another interesting point is EMC's spare disk designation. On an EMC a spare disk is always a spare disk. If a disk failure were to occur, the RAID group will rebuild using a spare disk. Once the failed disk is replaced, the RAID group is once again rebuilds on to the replaced disk. For each disk failure there are two rebuilds of the data. During this time a filer is most vulnerable to a second disk failure. There is also performance degradation during rebuilds. On the NetApp, there is only one rebuild of the data on to the spare disk. When the faild disk is replaced, it becomes the spare.

Some other features of the EMC are mirror root disk, battery backup, and write cache mirrored to disk on power outage. The battery backup of the EMC is not meant to keep the filer running indefinitely, just long enough to move the write cashe on to disk and shut down the filer gracefully. NetApp is using "motor cycle" battaries in F800 series filers to maintain the NVRAM. Though I have never run in to a problem where I lost the NVRAM contents due to dead battery, there is the remote possibility.

One other issue, if you are running in a mixed environment, EMC does not allow for both NFS and CIFS to be running on the same volume. Both, though, may be running on the same filer. NetApp does allow you to run both NFS and CIFS file systems on the same volume.

Just some thoughts.

-gdg

Rahul Kumar wrote:

Hi I am also interested in knowing for the same.... EMC was recently at our place and they claimed to be faster than netapp's like ops /sec etc etc. Their demo box is yet to come. If anyone has tested IP4700 let us know Thanks Rahul

-----Original Message----- From: Mike Ball [mailto:MBall@datalink.com] Sent: Tuesday, January 29, 2002 8:06 PM To: toasters Subject: IP 4700 vs Netapp

Has anyone tested a EMC IP 4700 in the last 6 months? EMC claims they have greatly improved the box in the last six months, but I have not been able to get any specifics as to what they have done. Thank you, Mike