[Info-vax] VSI OpenVMS V9.1 Field Test beginning.

[Stephen Hoffman]

On 2021-07-08 14:00:29 +0000, chris said:

> On 07/07/21 02:24, Stephen Hoffman wrote:
>> On 2021-07-05 16:48:38 +0000, chris said:
>> 
>>> On 07/02/21 18:29, John H. Reinhardt wrote:
>>> 
>>>> 
>>>> 1.32 SupportedDiskTypes
>>>> VSI OpenVMS x86-64 V9.1 only supports SATA disks. Support for other 
>>>> disk types will be added in future releases of VSI OpenVMS x86-64.
>>>> 
>>> 
>>> Find that odd. SATA are consumer quality, 5400 or 7200 rpm. so slow 
>>> access compared to U320 scsi or sas at 10 or 15k...
>> 
>> I can get ~half a gigabyte per second through a single SATA storage 
>> connection, sequential read or sequential write, on widely-available 
>> SATA (SATA 3.0 / SATA 6Gp/s) storage hardware.
>> 
> 
> That's with 7200 rpm drives, probably, whereas many are only 5400, so 
> doubt that would be sustainable  bandwidth over large files, or where 
> the drive needs to seek or change track.

That's sustained sequential reads and sustained sequential writes at 
roughly half a gigabyte per second.

> At 7200 rpm, track to track and rotational latency could be 8.4 
> milliseconds worst case + head seek time, which limits sustainable 
> bandwidth. 10K drives are better, 15K, even more so...

How old is this server gear?

Yes, a high-end SAS 15K HDD peaks around 200 to maybe 225 MBps 
sustained sequential, which is marginal for use on SAS/SATA 1 (2003), 
and comfortably within SAS/SATA 2.

SSDs are however faster, and can push the limits of what SATA 3 (2008) 
offers. The Integrity rx2800 i6 box offers SAS/SATA 3.

Or storage on yet faster buses such as NVMe via PCIe 3.0 (2013) or PCIe 
4.0 (2017), for those on more recent server gear. But VSI isn't there 
yet, with NVMe.

Specifically for the OpenVMS V9.1 beta, a hypervisor guest on SSD 
storage on SATA 3 buses should be more than adequate for most beta 
users.

Available x86-64 storage options and configurations are very different 
from those of Integrity and AlphaServer systems too, so many of us will 
spending time reading the VSI hardware support documentation.


-- 
Pure Personal Opinion | HoffmanLabs LLC