[Info-vax] Some I/O results

[Mark Berryman]

On 11/10/23 12:01 PM, Simon Clubley wrote:
> On 2023-11-10, Mark Berryman <mark at theberrymans.com> wrote:
>>
>> Now, how to get the data onto my VMS cluster?  The Alpha and Integrity
>> systems only have 1G Ethernet interfaces but the x86 system, as an ESXi
>> guest, has both 1G and 10G interfaces.
>>
> 
> [snip]
> 
>>
>> So, with SCP, the best I could manage was a copy around 5 MB/sec.  On
>> the other hand, a Mac to Mac copy - over the same 1G LAN - achieved over
>> 90 MB/sec, which is close to the maximum possible.
>>
> 
> I assume the Mac to Mac copy is also using SCP ? It's not completely clear.

Yes, it was SCP.

> 
>> With FTP, I could achieve around 14-15 MB/sec.
>>
>> My last option was NFS.  It managed better than 20 MB/sec.  It was also
>> much easier since I could NFS mount the source and then just use a copy
>> command to get the data and copy pre-allocates the destination file on
>> its own.
>>
> 
> Are delayed ACKs turned on or off on the VMS systems ?

I tried it both ways.  For this, there was little measurable difference.
Off hand, I can't remember which was slightly better.

> 
>> Now here is the part that was surprising to me.  As mentioned, the Alpha
>> and Integrity systems were copying over a 1G Ethernet path whereas the
>> x86 system was using a 10G path (the Mac has both 1G and 10G
>> interfaces).  Using the exact same source and exact same I/O sizes, the
>> Alpha averaged 335 I/Os per second to its target disk, the Integrity
>> system managed just over 400 I/Os per second, but the x86 system
>> couldn't do any better than 279 I/Os per second - even on a link that
>> was 10 times faster.  (It also has a faster HBA than the other systems).
>>
> 
> What type of disk ? Hard drive or SSD ?

SAS Hard drive.  All storage is located on the SAN.

> 
> It is possible the VM is causing some additional overhead ?

Possible.  But if I boot the system bare metal then I don't have access 
to the 10G interface (no support in VMS for it).  At 1G, the transfers 
rates are in the KB/sec range.

> 
> Anything in the Ethernet error and retry statistics from the usual tools ?

The Ethernet is completely clean.  No errors or retries.  Everything is 
full duplex with jumbo frames enabled.

Mark