EXCLUSIVE: What the Gen8 Microservers missed out on

More information has been leaked to me from a source inside the HP corporate machine regarding the features that were actually ruled out of appearing from the upcoming G8 Microserver models. The list appears to have a couple of items on it which at first glance seems out of place on what really is HP’s most basic server.

From what we could ascertain from our source, at the original product planning stage of the new model, the team basically throws all possible features and functionality that could possibly be put into the product onto the table, then rules each one out. Some features went further into the product planning process than others, but items taken out of the product specification is said to be ‘outscoped’.

Some of the outscoped features supplied to me were:

  • 12Gb/sec SAS support
  • Small Form Factor HDD cage (2.5″ Drives), either as an option or standard
  • External ‘SCSI’ interface (we assume SAS port)
  • Storage Expansion Unit (via SAS connector?)

There’s also something removed from the new Microserver too. So far we have ruled out any eSATA port, which the G7 did have. We think that the USB 3.0 ports will more than make up for the lack of eSATA, which could be difficult for some people to use.

SAS 12G

This one seems a bit out of place in such a low-powered ecosystem. 12G SAS is usually reserved for the high-end SSD drives, or multi-port HDD drives. Even then, if you need more storage speed, usually it would be cached to a PCIe-based SSD which has data transfer speeds well in excess of 12Gbps.

The target market for the Microserver G8 is for either SOHO storage, or for Branch offices that need a little storage but the ability to run remote Active Directory, DNS & DHCP plus maybe a print queue or two. SAS 12G just isn’t required!

Small Form Factor drive cage

The idea of an SFF cage in a device like this is not new – plenty of Microsavants have installed a 4 x 2.5″ drive cage into the 5.25″ ODD bay of the G7 Microservers. HP themselves started moving to SFF Drives in a number of the Proliant G5 range, notably the DL360 and DL380. Due to this, the DL380 G8 can now take up to 16 spindles with its SFF cages in a 2RU Chassis, whereas the DL380 G4 could only take six spindles with 3.5″ Drives in its 2RU Chassis.

The main benefit of more spindles is a higher aggregated IOPS (Input/Output Operations Per Second) over the entire array. This means more reads and writes can be performed, and applications need to wait shorter amounts of time for the data to be written to/read from storage.

There is a downside to the 2.5″ disk format. Basically the highest density drives in a 2.5″ format is currently 1TB. There are 2TB drives available from Western Digital but they either sport a Micro-USB3 interface and come as a external storage drive, or they are the ‘Green’ models and these do not play nicely with Hardware RAID controllers.

In the case of something like the Microserver, a 3.5″ bay means that 4TB can be stored with a 4TB Hard Drive. You cannot fit 4x 1TB 2.5″ drives into the space of a single 3.5″ drive, so by doing so you would actually lose density of storage by doing this. I also cannot see how this unit would require the sorts of performance required by more than spindles UNLESS it was being used as a highly storage-contended Virtualised Host, and even then your biggest problem is going to be CPU cycles. It’s not like there would be four Database VM’s fighting over disk as your CPU will not have the capacity for that.

What the SFF drives would do for the Microserver will make it easier to design, mainly as the drive bays are smaller and the HP Designers could orientate them differently in order to gain space and reduce the physical size of the unit. They could even or even fit more disks in without sacrificing space. On my quick estimate, I think you could fit 12 SFF drives where the current 4 LFF reside, and maybe still have some space left over. Still not going to have the maximum storage capacity of the current 3.5″ setup, but would get close. If decent 2TB drive were available, it would be a different outcome.

External ‘SCSI’ interface

I personally think this is the most interesting of the outscoped features. It would mean that you would get an External SAS port that you could use to hook up to external disk arrays. I have used a Promise VessRAID unit with Dual SAS interfaces at a client site to act as a shared ESXi Datastore. There are other 3rd Party RAID or JBOD enclosures that you can plug a workstation into. This storage is then presented to the machine through a Host Bus Adapter (HBA) card.

I have used a few SAS HBA’s with ESXi hosts, and they work well. The bandwidth available is very good, in most cases 600MB/sec transfers are very possible. It all depends on the array itself and how it is configured. It would have turned the little Microserver into a unit that could store some serious amounts of data and probably would have eaten into other HP product sales, so it was taken out of scope.

Storage Expansion Unit

This External Storage Array is the other half of the External SCSI Interface. This was mooted to be a modular box that looked exactly like the upcoming Microserver, however would only contain storage bays for drives, and a small SAS interface to manage them and connect it back to the Microserver, along with a power supply.

In this case, it was very much like the units you can get from NAS vendors which you can add/stack to your NAS to increase the storage capacity. One I can think off immediately is the Synology DS-513 which you connect to a ‘host’ NAS via an eSATA port, but gives you an additional 5x 3.5″ drives for storage.

Again, probably meant that the Microserver could store too much and take sales away from more powerful enterprise level storage.

Conclusion

There is really no surprise that these features were rejected by HP. Personally I find it rather exciting that they ever considered putting these sorts of technologies and features into the Microserver in the first place. To my mind, the idea of SAS 12G being baked into a sub-$500 server is equal parts terrifying, confusing and inspiring. For this, I applaud HP’s open thinking regarding the possibilities of their products.

It is quite a shame that the Storage Expansion Unit did not make the cut. This would have been very interesting and kept the Microserver look. But on the other side of that argument there is nothing stopping us buying a SAS HBA card and running that in our Microserver and connecting something like a 8-bay external disk unit to it.

The fact is that generally, HP has heard the cries of the community and acted upon them. 16GB Memory capacity, USB 3.0 ports, Dual NICs with teaming capability, and proper iLO Management have all been added to the product along with a very reasonable CPU upgrade. I think we can all be thankful that we got what we wanted.

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