CCRC'08 data transfers (part 2)

Just thought I would post a couple of plots to show the data transfers over the past couple of weeks. Things seem to have reached their peak of ~2GB/s last week and have now reached a steady state of ~1.2GB/s. These plots show transfers from all sites to all sites and it looks like the vast majority of the data appears to be going to the T1s.

I think during the ATLAS FDR exercises there will be much more data coming to the T2s from their associated T1. This should be good to help test out all that new storage that has been deployed.

CCRC May'08 data transfers

The plots above shows the slow ramp up in data transfers being run by the experiments during the May phase of CCRC. Clearly CMS are dominating proceedings at the moment. It's not clear what has happened to ATLAS after an initial spurt of activity. Hopefully they get things going soon, otherwise the Common elememt of CCRC might not be achieved. What is good is that a wide variety of sites are involved. You can even see the new Edinburgh site in there (although it is coming up as unregistered in GridView).

I'll take this opportunity to remind everyone of the base version of the gLite middleware that sites participating in the CCRC exercise are expected to be running. Have a look at the list here.

CMS CCRC storage requirements

Since I've already talked about ATLAS tonight, I thought it might be useful to mention CMS. The official line from the CCRC meeting that I was at today is that Tier-2 sites supporting CMS should reserve space (probably wise to give them a couple of TBs). The space token should be assigned the CMS_DEFAULT space token *description*.

DPM sites should follow a similar procedure to that for ATLAS described below. dCache sites have a slightly tougher time of it. (Matt, Mona and Chris, don't worry, I hear your cries now...)

ATLAS CCRC storage requirements

For those of you reading the ScotGrid blog, you will have seen this already. Namely, that SRMv2 writing during CCRC (which started yesterday!) will happen using the atlas/Role=production VOMS role. Therefore sites should restrict access to the ATLASMCDISK and ATLASDATADISK space tokens to this role. To do this, release and then recreate the space reservation:

# dpm-releasespace --token_desc ATLASDATADISK
# dpm-reservespace --gspace 10T --lifetime Inf --group atlas/Role=production --token_desc ATLASDATADISK

Note that at Edinburgh I set up a separate DPM pool that was only writable by atlas, atlas/Role=production and atlas/Role=lcgadmin. When reserving the space, I then used the above command but also specified the option "--poolname EdAtlasPool" to restrict the space reservation to that pool (I also only gave them 2TB ;)

Also, for those interested, here's the python code (make sure you have DPM-interfaces installed and /opt/lcg/lib/python in yout PYTHONPATH).

#! /usr/bin/env python
#
# Greig A Cowan, 2008
#

import dpm

def print_mdinfo( mds):
    for md in mds:
        print 's_type\t', md.s_type
        print 's_token\t', md.s_token
        print 's_uid\t', md.s_uid
        print 's_gid\t', md.s_gid
        print 'ret_pol\t', md.ret_policy
        print 'ac_lat\t', md.ac_latency
        print 'u_token\t', md.u_token
        print 't_space\t', md.t_space
        print 'g_space\t', md.g_space
        print 'pool\t', md.poolname
        print 'a_life\t', md.a_lifetime
        print 'r_life\t', md.r_lifetime, '\n'

print '################'
print '# Space tokens #'
print '################'

tok_res, tokens = dpm.dpm_getspacetoken('')

if tok_res > -1:
    md_res, metadata = dpm.dpm_getspacemd( list(tokens) )
    if md_res > -1:
        print_mdinfo( metadata) 

CCRC confusion

So, which Tier-2s are involved in the February CCRC exercise? Does anyone know? What about the date that they will get involved? Do they need to have SRM2.2, or not? Some sources suggest they do, others suggest they don't. If anyone knows the answers to these questions, please email me. I think I'll start attending the daily meetings to find out what is going on.

Also, it turns out that although the 1.8.0-12 release of dCache was made sometime last week, it turns out that this is also the CCRC branch of dCache. Do you spot the difference? Good, then we can continue. This explains the weird naming convention that the dCache developers are using for all CCRC related releases, namely 1.8.0-12p1, 1.8.0-12p2 for patch versions 1 and 2 of the 1.8.0-12 branch. Hope that clears things up.

Full chain testing

The experiments want to test out the complete data management chain, from experiment pit->Tier-0->Tier-1->Tier-2. This exercise has been given the snappy title of Common Computing Readiness Challenge (CCRC) and is expected to run in a couple of phases in 2008: February, then May. This will be quite a big deal for everyone, and we need to make sure the storage is ready to cope with the demands. SRM2.2 is coming "real soon now" and should be fully deployed by the time of these tests (well it *had* better be...), which will make it the first large scale test of the new interface.