Introducing P4500 to an existing P4300 site

[Erick Arturo Perez]

Hi,

As we dont have reference friends to ask for comments, I would like to know your opinions on the following setup:

We have four P4300 G2 that were upgraded to Lefhand 10.x

Now we have more needs for storage, We have two options, buying 2 or more P4300 storage nodes (BK719A) or buying a pair of P4500 (BQ888B). We need at least 12TB RAW space.

Since the disks are different (P4300 LFF 7.2K vs P4500 15K) I was wondering if there is any incompatibilities if we get a pair of the P4500 and introduce them as part of our existing P4300 single site SAN.

We have 1TB drives on the P4300 and Im reading the P4500 come with 600GB drives.

The P4300 currently serve 2 server nodes over iSCSI at 1Gbps. The server nodes run XenServer 6.x

The main reason to buy the P4500 is to get the speed of 15K drives.

Is this a recipe for problems? or should I continue to buy P4300 expansion untis?

Thanks,

P.S. This thread has been moved from HP 3PAR StoreServ Storage to HP StoreVirtual Storage / LeftHand. - Hp Forum Moderator

[Emilo]

if you mix the two different models in the same cluster they "dumb' down to the slowest common denominator.

in other words the p4500 will be as slow as the p4300 and will only be able to use that same amount of raw disk space.

You can though put them in different clusters and they should be fine.

[Erick Arturo Perez]

Interesting.
One thing that makes me wonder if we should keep with the P4300. In our case, we do RAID5 at hardware level and RAID10 at network level, so we always get a 50% of the total usable/purchased space.
Right now in order to achieve 12TB of DATA space, we need to buy 24TB of usable space. That is a total of 9 boxes of BK718 (8x450gb SAS disks) and 18U of rack space.

Oh, BTW my mistake. The P4300 we have are the ones that come with 8x450GB disks.

I wonder what will be the logical step in my case. Should I go buy a small EVA instead of 9 additional P4300?

Thanks.

[Emilo]

the advantage of the p4500 is the number of spindles increase because of the number of drives.

You will also pickup the speed of the sas drives.

EVA is very expensive compared to the LH product.

Dont forget to look at the underlying infracsture very closly as it is essentiall your SCSI connection.

Make sure your switches have sufficent buffer space and make sure you keep the SAN traffic segregated.

I dont know the EVA product very well all.

[oikjn]

if your current storage speed is sufficient, getting more 4300s will be the most cost effective way to upgrade the pure capacity.  If you get 4500s, those should really go into their own management group so they are utilized fully.  You can keep them in the same management group and that would allow you  to do manual tiering of LUNs and transfer luns between clusters if you wanted. 

You don't mention how many nodes you currently have because if you are adding 9+ nodes you can be comming up on either a cluster node limit or an iscsi initiator connection limit.

The simplest and cheapest way would be to get more 4300s as long as you have been ok with their base performance.  Adding more nodes will get you more total throughput and more IOPS, but won't help reduce the latency (as that is a pure function of drive RPM). 

[Steve Burkett]

If you're looking at new P4500 G2's to run in a stand-alone cluster, I'd consider going the newer HP Storevirtual 4330's with the larger 600GB or 900GB SAS drives. Only 10k disks in them, but HP say the newer disk controller and hardware of the Gen8 platform makes up for it not having 15k disks. I'd love to see some hard stats on that performance comparison from HP though.  Only 1U in size as well so you can pack them in.

Otherwise the new low cost HP 3Par 7000 looks the business. The EVA line looks to be pretty dead, with all the innovation and press going on the 3Par line. Looks like HP want to get existing EVA customers migrated over sooner rather then later.