EMC Sym 3830 vs HP XP256

[UNIX Administrator_1]

We are in the process of selecting a new storage unit and the Symm 3830 and XP256 are the finalist. I would like to know people's past/current experiences with one or both of these boxes (good and bad). I am looking for answers related to performance, experiences with HP and EMC service, and any other interesting facts that would be good to know.

We currently have an EMC Symm 3430 connected with 2 D and 4 K class servers. We are thinking about direct connecting, with FC, 4 N's and 2 L's into the new box. (We are in the starting phases of upgrading our datacenter.) We also have Sybase 11.9.2.

Thanks,
Paul

Sorry for the second post...I accidently put this in the disk, not disk array.

[Petr Cerny]

Hello Paul,
here are my comments.
- XP256 is definetely faster than 3830 (which is quite old). If you are considering to connect several servers, you can expect that XP256 will handle around 2000 IO/s on one FC port for each host. For single host you can sequetially read app. 50MB/s on FC port. Backend throughput is highly dependant on number of ACP controllers - how many ACP's do you have (or plan to have)?
- XP256 if off the product list since Dec 2000, the only way to get it is probably through remarketing channel, if ever.

Regards,

Petr

[Peter Mattei]

Hi Paul

You should see about the same performance for both, the EMC 3830 and the XP256, when configured in RAID01 and with the same disk sizes and numbers.
You will see a much better performance on the XP256, when configured in RAID5 (compared to RAID-S on the EMC)
I usually suggest using RAID01 for log files, indexes etc. and RAID5 for table spaces and other file systems.

Beside performance, there are some other differences:
1. On an EMC box you can only have 2 different disk types (e.g. 9GB, 18GB) at a time. On an XP256 you can have all different sizes installed that were ever available (15, 18, 36, 47 and 73GB) at a time.
2. Microcode. EMC usually wants to upgrade microcode during an offline period. If they do have to upgrade concurrently, the I/Os have to be brought down to below 300 IOPS for the box.
EMC has only one copy of the microcode in the machine. So if a problem occurs, the machine has to be brought offline and the microcode be installed from scratch.
On the XP256 you have multiple copies of the microcode. HP does concurrent microcode upgrades on a regularly basis. I necessary, you can go back to the previous copy concurrently.
3. The XP256 has all parts redundant. The cache is mirrored and even the disks have dual SCSI ports. The EMC has no mirrored cache and the disks are single ported.
4. The remote support modem line on the XP256 is based on a call back function. So nobody can dial in directly. On the EMC you can!


Best regards
Peter

[Dave Wherry]

Just to add a couple of more things. You have more control over the XP than the EMC. When you want to add a LUN to a port you can do it on the fly. EMC requires a bin file change and reboot of the frame.
You would have to go with a used XP256. It had been replaced by the XP512 and XP48. These new frames are fibre throughout and perform much better.

I've had acceptable and bad support from both companies. For me they are about even there. All things considered I would go with an XP.

[Alexander M. Ermes]

Hi there.
Just my two cents to this message.
We use EMC right now, but we have to do a decision, what to do in the near future.
I tend to the XP solution.
The XP is on a later technical standard than the EMC. EMC did not keep up with techniques, that the XP uses now.
Support depends mostly on the people taking care of it, but if you go for XP, you have everything in one hand.

Now my word is to take the XP.
Rgds
Alexander M. Ermes

[Paul R. Dittrich]

When we purchased our XP256 it was the end result of a detailed FMEA (Failure Modes and Effects Analysis).
The XP256 won because we could not find any single points of failure anywhere in the system while the EMC still had at least one - a single copy of the microcode.

We've been quite pleased with our XP256 performance and satisfied with the service.