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This page contains information on how to manage the ALICE beast machine.
For a description of the machine hardware and WIP click here
system SSD (M.2) 90GB / # system root /opt # folder for user software /var # folder for logs and other runtime things /tmp # temporary folder emergency admin user homes SSD (M.2) 90GB /ahome >>>> There is still time to change these. Please speak up. I could for example allocate more space for system and opt instead of the one allocated for /ahome. <<<< user homes SSD (U.2) 690GB /home # user home folders data disk (RAID6) 55TB /disk # available for data, filesize >= 1MB
Direct access to root user is discouraged. Administrators should use the sudo
command to become root.
There is a special user whose home folder is located in /ahome
in case the home folders get corrupted, called alicedrift
. You are free to create a password for such user and share it among the group. I recommend you do this asap. This is to be used in case of emergency.
To elect a new administrator, it is enough to add them to the wheel
unix group.
Fiddling with sudo configuration files is strongly discouraged.
usermod -aG wheel <username>
Example:
usermod -aG wheel pflorido
I suggest you install system software according to the distribution, using yum
.
As for research software, I would recommend you install:
/opt
folder (SSD) /home
(SSD U.2)/disk
folder (RAID)
For system/distribution software installation it is recommended to use the yum
command and the rpm
system. Centos7 is a RedHat based distribution. The commands are pretty much the same as ubuntu. Here I give you a quick reference of most useful commands.
yum search <string>
Example:
yum search tmux
yum install <packagename>
Examples:
yum install tmux
yum provides */<expression>
Examples:
yum provides */libboost*
yum upgrade
You will be asked to accept the changes.
:WIP:
This section describes how to handle some critical situations.
In what follows I will use terminology that I clarify below.
This can happen if one or more of the RAID disks are broken or starting to fail. You are supposed to take action asap.
How to detect?
What to do
There are two U.2 disks in software RAID serving user homes. Should one disk fail, the homes will continue to work, but as soon as possible you are required to replace the broken disk to avoid data loss.
This can happen if one of the U.2 disks containing home folders is faulty.
How to detect?
What to do
The system M.2 disk is in software raid with two partitions of the U.2 disk. This allows the machine to continue working when the M.2 disk is faulty. However, the machine will not reboot in case this disk breaks. Unfortunately the U.2 disks cannot be used for booting. It is a limitation of the machine.
Nevertheless it's possible to entirely restore the disk image by copying one of the two copies in the U.2 drives. See description below.
How to detect?
What to do