[Info-vax] Multi-site OpenVMS field upgrade options?

[Stephen Hoffman]

On 2019-04-15 12:16:46 +0000, Rod Regier said:

> Floor for SFF SAS drive controllers is RX2660. Very few of those in my 
> installed installed base systems are running those.
> Installed base unlikely to sustain pricing of whole sale upgrade of 
> DS10L, DS15 and RX2600 units to RX2600 units or beyond.
> ...
> The list for Nemonics alleged "new" drives is impressively long - over 
> 100+ different models spanning over a 15 years of product evolution.
> Makes me skeptical they are "new" in the sense of an actual drive SMART 
> data reporting under 5000 hrs of actually spin time.

There is seemingly some unfamiliarity with hardware availability, and 
the current necessity to compensate for the usual limitations of app 
software, and also with the associated limitations of OpenVMS.

Unfortunately, modifications to the apps to ease these inevitable 
storage and server transitions are perceived as being far more 
difficult or more expensive than are these manual transitions.  Server 
replication is not commonly seen with OpenVMS apps, but it's common 
with other sorts of clustering.

App developers on many platforms and for many apps seemingly have to be 
dragged into supporting upgrades and migrations.  Which doesn't help.

SFF drives are serial SCSI (SAS, SATA), and those are readily 
available.  So not an issue here.

New parallel SCSI SCA hard disk drives are available, and will work 
when internally mounted and configured with the proper parallel SCSI 
adapters.  "Cage-free" AlphaServer DS15 systems have several internal 
bays that can be used, for instance.

Might want external shelves, if you're working with vendor storage 
cages and vendor-provided removable storage devices.   Storage upgrades 
are quite possible within the bricks of the ancient StorageWorks SBBs.  
Newer removable mountings, less feasible.  Which is where Nemonix 
provides adapters and firmware to allow newer storage to mimic the 
older storage.  Call'm and ask if they can offer new storage for these 
and similar storage replacements.  AFAIK, they can provide new storage 
here, and not refurbs.  
https://www.nemonix.com/pdfs/NxDatasheet_NXRZ_ST.pdf    But for 
parallel SCSI configurations, SCA adapters will probably work for your 
needs, given somewhere to mount the SCA drives, and not-ancient OpenVMS 
versions.

IIRC, Alpha never officially supported serial SCSI controllers, and 
Integrity didn't officially support serial SCSI controllers prior to 
the PCIe-enabled servers.  (SAS and SATA need the PCIe bus bandwidth, 
and particularly for the SSDs.)  So serial storage storage whether SSF 
or otherwise less interesting for the pre-PCIe server boxes.  And 
whether unsupported SAS/SATA PCI-X controller configurations can be 
gotten to work, there are still parallel SCSI drives with SCA available 
for the older server boxes.

Beyond reworking the apps to make these swaps easier to deal with, 
establishing a server replacement cycle is another and overarching 
issue here.  The AlphaServer DS10L gets "toasty fun" when the thermal 
paste under the heat sink finally dries out and crumbles, for instance.

This whole server migration mess is a slog of our own app development 
(mis)practices, unfortunately.  OpenVMS has never been good at this 
stuff, and clustering and the rest of OpenVMS are just plain bad at 
providing app development support—effectively none—for these app and 
server migrations.  OpenVMS allows and variously encourages scattering 
app files and data all over the place.  (macOS is vastly better at 
wholesale app migrations, for instance.)  Typical would be app-level 
shadowing of data across servers, whether using RabbitMQ or some other 
scheme.  https://www.rabbitmq.com/clustering.html  Etc.

Yeah, retrofitting assistance for server migrations into apps gets 
gnarly.  But we're never not going to be migrating to newer servers, 
and we're headed for more migrations given the shorter replacement 
cycles expected with x86-64 servers.

TL;DR: what has to happen for a server migration varies, and a server 
migration is as much dependent on the app (software) details as on the 
server (hardware) details.  If not more so.  The messes here are almost 
always of our own apps' doings and not-doings, too.



-- 
Pure Personal Opinion | HoffmanLabs LLC