VMAX is modular and Eternus is not really enterprise class, having several limitations, according to an EMC fan. Fujitsu says the person is ill-informed.
The fan, a "person familiar with VMAX matters", said they wanted to set the record straight, using an EMC ruler of course, regarding our story about Fujitsu's Eternus DX8700 S2.
The person had four points to make, namely that:
- contrary to Fujitsu's implications, VMAX was modular and not monolithic;
- the DX8700 S2 could only scale capacity in a limited way;
- the DX8700 S2 had limited SSD capacity;
- and the DX8700 S2 had no IBM mainframe connectivity.
We passed these views on to Fujitsu and Marcus Schneider, director of storage product marketing, responded. His replies follow each of the EMC fan's views.
In more detail...
EMC fan (first point): "With VMAX, the Symm architecture left the area of monolithic systems and now is as well fully modular. One can scale from one to eight engines (or even beyond in a short timeframe), from 16 to 128 four-core CPUs, from two to 16 backend- and front-end directors, all with up to 16 ports.
"A customer can start with only 48 drives... and could scale up to 2,400 drives (or even 3,200 in a short timeframe). And the whole entity can be expanded during normal operation without any downtime, from the smallest to the biggest configuration. If this cannot be called "modular", I do not know what could."
"The only valid comparison to Eternus DX8700 S2 is VMAX, which scales from 2 to 8 engines. But adding engines to VMAX forces customers to add disk drives as well, and by scaling beyond a certain disk capacity, customers are forced to increase the number of engines.
"There are no such restrictions with Eternus DX8700 S2. Theoretically a two-controller basic configuration can operate the total number of disk drives – up to 3,072 2.5-inch disks ... Of course it’s questionable if this makes sense in terms of performance, but it’s possible.
"And the other way round you could run a minimum of drives full blown by 8 controllers (take SSDs and you have a machine from hell). Does the VMAX “modularity” also include software licensing?... How about using the same 2U disk shelves from very entry RAID up to high-end; does that work with VMAX?"
EMC fan (second point): "Yes, the Eternus could scale up to around four terabytes of capacity. This capacity can only be achieved using two- or three-terabyte drives with SATA-interface, jeopardising all questionable advantages of the SAS-backend with six gigabits. These configurations are pure show-offs without any relation to day-to-day operations."
"In addition Eternus customers can flexibly choose and intermix disk drives with 2.5-inch up to 1TB and 3.5-inch up 3TB while VMAX offers 3.5inch only. Eternus DX (S1 and S2 in the entry, S2 everywhere) does not use SATA drives, but “Nearline SAS” drives which have dual-ported native SAS interfaces with SAS firmware; no SATA conversion required. The 6Gbit/s SAS performance is not required per drive, but to have the bandwidth within the enclosure and between enclosures (with x4 links = 24 Gbit/s)."
EMC fan (third point): "You forget to mention that the Eternus, even the biggest one, only supports 32 solid state drives (SSD) when launched. So, with up to 3,072 drives, the customer could only get one percent of the capacity in SSD. Real enterprise-arrays like IBM's DS8800, HDS' VSP or (certainly) our Symmetrix support 10-15 times more capacity; a VPLEX can actually be ordered SSD-only with up to 960 drives."
"All systems, beginning with Eternus DX80 S2, can be equipped with SSD up to the total possible number of disk enclosures: meaning not 1 per cent but 100 per cent of capacity – or 3,072 disks – in a DX8700 S2 can be SSD.
"[Points] 2 and 3 are strange points: Some applications/data need performance, others need capacity. We at Fujitsu do not take decisions for our customers [about] what make sense or not, we provide the tools to create an infrastructure that meets their needs.
"That’s why you can scale the number of controllers independently from the number of disks. By choosing a combination of controllers, SSD, SAS or Nearline SAS drive you can create a system that can exactly meet needs in terms of speed or capacity. To call big capacity a “show off” might be an indication that someone is getting pretty nervous?"
EMC (fourth point): "There is still no chance to plug IBM mainframes into the Eternus since it only provides FC- or Ethernet-ports. This disqualifies the Eternus from being called an "enterprise array" at all..."
"Anyway there are other mainframes, as well as those from IBM, and Eternus of course supports mainframes like the Fujitsu mainframes and BS2000. Due to our family concept we can also offer our midrange systems in this space. (And even EMC should have realized that “Enterprise IT” hasn’t meant mainframe only for a couple of years.)
"Well, and in the same moment as IBM offers open connectivity with FC, or FCoE or iSCSI we will be ready."
Well, fan of the big boss on the storage block has spoken and Fujitsu has spoken back. We have a sort of debate going on here. Some of the Fujitsu implications about VMAX have been denied by EMC. Some of our EMC fan's points about the Eternus DX8700 S2 are wrong. Overall a big architectural difference between VMAX and Eternus is the EMC internal network, the Virtual Matrix.
Which array is better for you is going to depend on lots of things but whether one or the other is modular or not is seems a sterile question. These are both highly capable arrays and deciding between them for a particular storage application is going to need some serious consideration. ®