Thanks
Information will be forwarded to appropriate people in D-Cache team
Regards
Owen
-----Original Message-----
From: Brew, CAJ (Chris)
Sent: Thu 6/1/2006 3:42 PM
To: Synge, OM (Owen); [log in to unmask]
Subject: RE: dCache and xrootd
Hi,
> -----Original Message-----
> From: Synge, OM (Owen)
> Sent: 01 June 2006 13:53
> To: Brew, CAJ (Chris); [log in to unmask]
> Subject: RE: dCache and xrootd
>
> Thnakyou all for information about xrootd. The D-Cache team
> would love the results to be verified as they have difficulty
> accepting that thier xrootd server could run faster than
> xrootd native server and suspect that maybe you have
> optimised your dcache more than the xrootd server?
Neither server is particularly optimised but off the top of my head I suspect that the xrootd server is coming off an older server with slower disks.
> Thankyou both Kostas and Chris for pointing out quite
> correctly that the xrootd door does not yet have
> authentication and cannot yet be configured to support
> readonly access.
>
> I have requested from the dcache team that they make a change
> to the door configuration so that the xrootd door supports
> read only access and can be configured with read only access.
> They are pleased to say this change will be done very soon
> and is now a high priority, and a new beta dcache xrootd rpm
> will come in the near future. We discussed errors, and they
> dont yet know what sort of errors they will get from the
> clients when readonly access is configured from the client
> that trys to write as they do not control an xrootd client code.
I'm not sure either but the xrootd setup here at RAL is configured read-only so it's a certainly a setup the protocol supports as is does for having some servers/filepaths read-write while others are read-only.
> Thier maybe a longer wait for security on xrootd as the
> Dcache tream have no knowlage about xrootd and this protocol
> with repect to security, do you guys know who to contact to
> find out about how xrootd security should/is implemented.
Again from what I know of the architecture that shouldn't be too difficult. The native server has plugins that handle different authentification methods.
Andy Hanushevsky ([log in to unmask]) is the ultimate expert, Pete Elmer ([log in to unmask]) might be able to help or I think all the main xrootd developers are on the xrootd mailing list ([log in to unmask])
Yours,
Chris.
>
> Regards
>
> Owen
>
> PS
>
> RAL's M$ web client has no spell check so sorry for typos etc
>
>
>
>
> -----Original Message-----
> From: GRIDPP2: Deployment and support of SRM and local
> storage management on behalf of Brew, CAJ (Chris)
> Sent: Thu 6/1/2006 12:19 PM
> To: [log in to unmask]
> Subject: Re: dCache and xrootd
>
> Hi Owen,
>
> Simple file access test comparing accessing 2.4GB babar
> collection (2 files - 1.6GB and 800MB) from normal xrootd
> setup and from dCache via xrootd door using 'time'
>
> xrootd
> ------
> real 15m27.020s
> user 10m10.470s
> sys 0m17.620s
>
> dCache over xroot
> -----------------
> real 11m37.365s
> user 9m44.490s
> sys 0m14.300s
>
> I can't really hammer it since it's running on my production
> system but I'll try to do a couple of slightly heavier tests
> and post the results.
>
> Could you ask if there's a way to configure it read only?
>
> Yours,
> Chris.
>
> > -----Original Message-----
> > From: GRIDPP2: Deployment and support of SRM and local storage
> > management [mailto:[log in to unmask]] On Behalf
> Of Synge,
> > OM (Owen)
> > Sent: 01 June 2006 11:45
> > To: [log in to unmask]
> > Subject: Re: dCache and xrootd
> >
> > I just told the D-Cache team, and they where delighted that things
> > have not yet broken for you, thier instant answer was can we have
> > performance numbers
> >
> > So please when you have got more results tell us all and I
> will pass
> > on your good new to D-Cache.
> >
> > Patrick also asked if he could quote you as having installed xrootd
> > for D-Cache.
> >
> > I guess that will have to wait a little, until all the tests are run
> >
> > Regards
> >
> > Owen
> >
> >
> > PS
> >
> > M$ web access has no spell check so sorry for my spelling
> >
> > -----Original Message-----
> > From: GRIDPP2: Deployment and support of SRM and local storage
> > management on behalf of Brew, CAJ (Chris)
> > Sent: Wed 5/31/2006 5:24 PM
> > To: [log in to unmask]
> > Subject: Re: dCache and xrootd
> >
> > Hi,
> >
> > Having just fixed my other problems on my dCache system I
> thought I'd
> > create some more for myself.
> >
> > But disappointingly this just seems to work. Installation
> was as per
> > this instructions and straight away I was able to run some of the
> > BaBar tools against it.
> >
> > I'll run a few more tests against it but so far it looks good.
> >
> > Chris.
> >
> > One more step in BaBar's plan for world domination done. Mwahahahah!
> >
> > > -----Original Message-----
> > > From: GRIDPP2: Deployment and support of SRM and local storage
> > > management [mailto:[log in to unmask]] On Behalf
> > Of Greig A
> > > Cowan
> > > Sent: 31 May 2006 09:46
> > > To: [log in to unmask]
> > > Subject: dCache and xrootd
> > >
> > > Hi all,
> > >
> > > Just to let you know that you can now get your hands on the
> > > (beta) xrootd
> > > door to dCache. Download the tarball from here:
> > >
> > > http://www.dcache.org/downloads/releases/dcache-xrootd-0.9beta.tar
> > >
> > > Looking at the installation notes, it is relatively trivial to
> > > install, just drop it into /opt/d-cache on each of your
> > dCache nodes,
> > > configure a file, restart dcache-core and -pool, and then
> > open up the
> > > xrootd door on the node(s) that you want to run it on:
> > >
> > > /opt/d-cache/jobs/xrootdDoor start
> > >
> > > It is not yet integrated into YAIM, but Owen may be
> working on that
> > > while he is in DESY.
> > >
> > > Note that they claim it is a beta release, so only a
> subset of the
> > > xrootd protocol has been implemented and xrootd transfers are not
> > > authenticated.
> > > I haven't been able to try it yet since I do not have ROOT
> > installed
> > > on any nodes.
> > >
> > > Let me know how you get on if you give it a go.
> > >
> > > dCache-xrootd 0.9beta release notes:
> > >
> > > -extends dCache to offer file transfer based on the
> Xrootd protocol
> > > -allows access of dCache files (read/write, random access)
> > from within
> > > ROOT in a transparent way -implements current Xrootd
> > protocol version
> > > 2.4.5 (production) -tested with TXNetFile (main
> > xrootd-client as it is
> > > found in the latest ROOT version) and xrdcp (also
> contained in the
> > > ROOT distribution)
> > >
> > > -requirements:
> > > #running dCache instance (production version 1.6.6)
> > >
> > >
> > > -limitations:
> > > # only a small subset (the main xrootd messages
> like login,
> > > open, read, write, close) of the Xrootd protocol is
> > implemented so far
> > > # async file transfer not yet supported (the
> > kXR_async flag in
> > > open requests will be ignored by now)
> > > # authentitication not yet implemented (no access
> > control at
> > > the
> > > moment)
> > >
> > >
> > > Cheers,
> > > Greig
> > >
> > > --
> > > ==============================================================
> > > ==========
> > > Dr Greig A Cowan
> > > http://www.ph.ed.ac.uk/~gcowan1
> > > School of Physics, University of Edinburgh, James Clerk Maxwell
> > > Building
> > >
> > > TIER-2 STORAGE SUPPORT PAGES:
> > > http://wiki.gridpp.ac.uk/wiki/Grid_Storage
> > > ==============================================================
> > > ==========
> > >
> >
>
>
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