On 30/07/15 17:24, Ewan MacMahon wrote:
>> -----Original Message-----
>> From: Testbed Support for GridPP member institutes [mailto:TB-
>> [log in to unmask]] On Behalf Of Matthew Mottram
>> For QMUL the remote loading still hangs, followed by an error like: Error
>> in <TNetXNGFile::Open>: [FATAL] Connection error. I guess I’ll go through
>> and compile a list of sites that we have problems at and ticket them.
> QMUL is a bit of a special case because their SRM is running StORM, its xrootd implementation is different and I don't think we'd expect it to work without a bit of extra setup (which is the subject of ongoing thinking, so it's very much a matter of not being expected to work /yet/. Hopefully soonish though).
> Of the other UK sites advertising storage for t2k.org:
> - Manchester, Lancaster, Liverpool, Sheffield and Oxford are all running DPM, and should work,
> - Imperial and RALPPD are running dcache and probably should work,
> - The Tier 1 runs Castor.
> I would suggest just not trying xrootd at QMUL for now until we get something sensible worked out there.
re xrootd, I asked several times if there was a sensible way of
configuring xrootd for multiple VOs. I never ended up with a sensible
config - though I do vaguely remember some answer that seemed vaguely
sensible from Brian Bockleman in person, I forget what the answer was
Is https an alternative? StoRM supports it - and it should perform
reasonably. Given that it is a config option for DPM, the dCache
developers seemed to prefer it to xrootd, and Atlas were encouraging its
deployment, that only leaves Castor.
Performance at QMUL would be limited to one https server - as opposed to
around 100 disk servers - so be aware it will be limited.
For one of analysis, reading data over the WAN will be doable - but be
aware that it will impact performance - all sites have considerably more
internal bandwidth than WAN bandwidth.
Of course, it sounds like what's needed here is some sort of "open the
file by the most efficient protocol from the nearest site" file stager