Yes, eventually dCache at Tier 1 will be phased out.
Nevertheless, we will continue to support dCache as long as
Tier 2s are running dCache - subject to funding from GridPP
and having enough people - at least we intend to support it
as much as we can.
In fact we can use CASTOR today; at least the SRM appears
to be working and our friends in CMS will be brea^W testing
it Really Soon Now(tm). Data is not kept, though, we're
still testing.
Anyone wants to have a go, let me know. There's a dteam
allocation too.
Now I am curious why "effectively" srmcp can't be used with
CASTOR? It works fine for me. Anyone knows or should I
ask Lassi?
Cheers,
--jens
PS. Quite enjoyed "WLCG is not easily moved by technical facts"
:-)
-----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: 05 June 2006 10:49
To: [log in to unmask]
Subject: Re: FW: FTS and Phedex
> " With RAL moving to Castor " RAL aren't getting rid of their dcache are they?
Yep, they sure are.
They should be using CASTOR by the end of the year I think. Jens can tell
you more.
Greig
>
> On 05/06/06, Olivier van der Aa <[log in to unmask]> wrote:
> > FYI, Lassi could not cc to the storage list.
> >
> > Cheers, Olivier.
> >
> > -------- Original Message --------
> > Subject: Re: Disabled Castor/Castor load test transfers
> > Date: Sat, 3 Jun 2006 17:31:14 +0200
> > From: Lassi A. Tuura <[log in to unmask]>
> > To: [log in to unmask]
> >
> >
> > *** Discussion title: PhEDEx Discussions
> >
> > Hi,
> >
> > > The iowait we observed happened when we where doing dCache->dCache
> > > transfers using fts.
> > >
> > > You can see the iowait difference between srmcp and fts on this page
> > > http://www.gridpp.ac.uk/wiki/IC-HEP#Transfer_Tests_2006-02-22
> > >
> > > We compared how the data is writen on the disk when using fts or srmcp
> > >
> > > http://www.hep.ph.ic.ac.uk/~georgiou/dcache_fts/fts-0.png
> > > http://www.hep.ph.ic.ac.uk/~georgiou/dcache_fts/srm-0.png
> > >
> > > you can see the difference yourself. Basically using fts causes the
> > > disk to jump when writing while srm doing fine.
> >
> > Thanks Olivier. Tim Barrass circulated these notes around before, so
> > we are aware of the situation.
> >
> > > The transfer rate we could achieve using srmcp (with phedex) was
> > > close to 400Mb/s while with fts we never reached more than 140Mb/s
> > > for dcache->dcache transfers.
> > >
> > > More tests haven been achieved by configuring the fts channel to
> > > use srmcp rather than gsiftp third party copy. It improved the
> > > situation but not dramatically. There will be an upgrade to 1.5 at
> > > ral next monday and I hope we can make another set of tests.
> >
> > I understand. We still need to move to using FTS. The weekly WLCG
> > service meetings are a good place to raise your concerns about the
> > performance. You should make sure Ian / Micheal / Stefano raise that
> > issue as they participate in those meetings, but you should be aware
> > that WLCG is not easily moved by technical facts.
> >
> > Please do keep in mind that we effectively cannot use srmcp against
> > Castor/SRM at this time, and most sites do not respond to problem
> > reports concerning srmcp, or do nothing about them. The reality is
> > that in practice WLCG only supports the subset of SRM used by FTS.
> > With RAL moving to Castor you would do well exercise your technical
> > options earlier rather than later so you can back your position with
> > clearly articulated numbers.
> >
> > Lassi
> >
> > -------------------------------------------------------------
> > Visit this CMS message (to reply or unsubscribe) at:
> > https://hypernews.cern.ch/HyperNews/CMS/get/phedex/207/4/1/1/1/1/1/2/1.html
> >
> > --
> > - O. van der Aa - Imperial College London -
> > - LT2 Technical Coordinator -
> > - tel: +442075947810, +442071005426 -
> > - SIP: [log in to unmask] -
> > - fax: +442078238830 -
> > - http://surl.se/agtu -
> >
>
--
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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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