Last modified 11 years ago Last modified on 07/06/10 17:38:53

dCache Tier I meeting July 6, 2010

[part of a series of meetings]

Present, IN2P3(), Sara(), Triumf(Simon), BNL(), NDGF(), PIC(Gerard), GridKa(), Fermi(), CERN()


(see box on the other side)

Site reports


Gerard reported that, in production, everything is OK.

On Wednesday, they're planning on upgrading PIC to 1.9.5-21.

Gerard also reported that he's planning on splitting off the Tier-2. Currently, the PIC Tier-2 is embedded within the Tier-1. The motivation is that PIC can migrate to a more recent branch of dCache, to give end-users access to the more advanced features that are available in the newer versions (such as NFS) and to provide the Tier-1 experience at running newer versions of dCache, ahead of deploying them within the Tier-1 instance.

The plan is to play with the splitting-off process for the next 2--3 months. This process will involve moving some 300 TB of data and a pnfs-to-Chimera migration.

If all goes according to plan, the splitting off will take place in October.

Gerard asked which version he should use?

We have just released 1.9.9-1. This is a normal short-lived feature release. Starting with 1.9.9, these short-lived releases will be supported for 9 months; previous releases were supported for 6 months. 1.9.9-series will be supported until 1st April 2011.

We plan to release 1.9.10-1 about the same time that time. This release will be supported until July 2011; however, PIC wouldn't be able to test their splitting-off process with a 1.9.10 release.

Also salient is that we are planning on making another golden release: 1.9.12. This is to allow people to receive long-lived support for a version of dCache that has WebDAV, NFS 4.1, etc. We plan to release 1.9.12 "Spring 2011" (1st April).

So one option would be to use a "short lived" feature branch initially (1.9.8 or 1.9.9, for example) and, later on, migrate to 1.9.12 for the "golden" support.

Having just release 1.9.9-1, we are now working on releasing 1.9.8-2. We will mark 1.9.8-2 as "green". With 1.9.6-series no longer supported, we would recommend people upgrade to 1.9.8.

We may make another bug-release for the 1.9.7-series (1.9.7-3), but we're unlikely to mark this release "green". This is because there is only 3 months left of support for the 1.9.7 branch, so we would recommend people upgrade to the latest 1.9.8- or 1.9.9-series release instead.

In August, DESY will upgrade one of their production instances to either 1.9.8- or 1.9.9-series.


In production we are OK.

Simon reported that, on one of their pool nodes a RAID-6 system suffered two disks failed at the same time (!). They are now using dCache migration to move files away from this node. This activity is moving some 7 TB of data to other pools.

Does migration module do checksum?

In fact, the migration module uses the same pool-to-pool transfer mechanism as all other dCache transfer activity. Whether a pool-to-pool transfer triggers a checksum configuration is determined by the configuration of the destination pool. If that pool has "On-write check enabled" then migrated data will be checked.

Simon also asked if there is any progress with ticket RT-5696 (describing how gPlazma didn't seem to work with an SCAS instance).

Paul: sorry for the delay, we'll chase this one up.

Support tickets for discussion

[Items are added here automagically]


Same time, next week.