Build root like exactly like the setup in lxplus

ROOT
1

Hi All:

Is there an optional or a script to build root in local computer exactly the same as that in lxplus?

The question I ask is because of:

  1. in atlas software tutorial, they have the scripts that one can build root with other dependencies downloaded with their scripts.

  2. I didn’t know the detailed setup of the built root in lxplus, especially the lcg root

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ROOT Version: Not Provided
Platform: centos 7.9
Compiler: gcc 8.3.0

2

Which “ROOT in lxplus” - you mean /usr/bin/root? That’s not LCG but EPEL; you’d have to check how the the EPEL ROOT builds are configured.

Despite your explanation I don’t understand yet why you need to know?

3

Hi @Axel,

Sorry for the late reply.

I’d like to build the root, like:

/cvmfs/sft.cern.ch/lcg/releases/LCG_97a/ROOT/v6.20.06/x86_64-centos7-gcc8-opt/bin/root

or

/cvmfs/sft.cern.ch/lcg/releases/LCG_97_ATLAS_1/ROOT/v6.20.02/x86_64-centos7-gcc8-opt/bin/root

with the exact setup of these versions.

Other root versions I’d like to build are here, via commands:

setupATLAS
showVersions root
4

Hi,
That’s still what you try to do, not why. Could you explain why you need this? I’m asking to be able to give you an answer on how to achieve what you need.
Cheers, Axel.

5

Hi @Axel,

Thanks a lot,
The reason why I build the root is due to my network to cern lxplus. As my location is a bit far away from cern, there is a latency (about 2 seconds) for each commad. You could imagine how annoying it is.

I’ve already installed centos 7.9, gcc 8.3.0, athena(with different versions), and root with different versions in my laptop. But the root I built is a bit different with the root in lcg, though with the same version. The setups are different, which give me some trouble to do physics analysis.

That’s why I’d like to build the root version exactly the same as that in lcg.

cheers,
Yingjie

6

Hi,
Thanks for explaining. What you should do then is to install cvmfs: it takes exactly the same binaries as you have on lxplus. Please contact your ATLAS mailing list / forum to understand how to set that up.
Cheers, Axel.

7

Hi Axel,

Thanks a lot,

Actually, I’ve tried this option several days ago, but during running, it’s very slow even open a root(like 3 to 5 minutes). I think this is still based on the online root.

Or maybe one possible way, I’d like to know the lcg root build options, and the dependencies. If I miss some libraries, I will try to download and build.

Cheers,
Yingjie

8

Hi,

Only the first time. It caches all files. Try a second time and it’ll be blazing fast: all required files are then local.

The time it will take you to reproduce the build environment for an ATLAS LCG build is way, WAY, larger :slight_smile:

Cheers, Axel.

9

Thanks, though, after I restart my computer, all caches are lost.

10

That sounds wrong - it’s using your disk to cache files. Luckily we have the expert on cvmfs here: @jblomer can you help diagnose what’s wrong with the cvmfs setup?

11

Thanks so much, the major function I am concerned is: how to keep the caches permanently, or at least a long time.

Cheers,
Yingjie

12

By default, the cvmfs cache is stored in /var/lib/cvmfs which should survive reboots. Please run cvmfs_config showconfig sft.cern.ch and paste the result, which can help me understand if there is any obvious issue with the configuration.

13

Hi @jblomer:

After I restart my computer, I found there is nothing under /cvmfs/(the reason why I thought caches are lot), but /var/lib/cvmfs survives. So when I run the same command, it becomes faster(though some commands are still slow, but tolerable).

Thank you and @Axel!

I attached my output in case you find something wrong.

Cheers,
Yingjie

cvmfs_config_showconfig_sft-cern-ch.txt (3.5 KB)

14

If you plan to use the cvmfs a lot, edit the “/etc/cvmfs/default.local” file and
increase the “CVMFS_QUOTA_LIMIT=100000” (then “sudo cvmfs_config reload”).

15

cheers,

16

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