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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
The machine is only accessible within the hep network as it was for aurora. One must login to teddi first if outside the division. This can be changed but at the cost of some security service always running in the machine, and me monitoring what happens in terms of logins.
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. Store the password in a secure place.
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>
usermod -aG wheel pflorido
I suggest you install system software according to the distribution, using
As for research software, I would recommend you install:
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>
yum search tmux
yum install <packagename>
yum install tmux
yum provides */<expression>
yum provides */libboost*
You will be asked to accept the changes.
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.
The HW RAID is the big storage with lots of data. It should resist two broken disks before total failure (loss of data, unreadable data).
A list of commands to interact with the RAID is here: storcliqr
How to detect?
storcli /c0/v0 show all
and verify there are no errors reported.
What to do
#show background activity storcli/c0/v0 show bgi
# show array initialization or rebuild storcli/c0/v0 show init
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?
for i in 5 6 7; do mdadm --detail /dev/md12$i; done
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 - : requires own page
1. Identify the broken raid disk. If it is one of the U.2 disks, then the procedure is slightly easier. One can skip steps :[number of steps]
2. Mark the RAID disk as faulty if the system did not do automatically.
3. Remove the device from the array.
4. Shut down the machine.
5. Replace the broken disk.
6. start the machine using sysrescuecd.
7. Create the proper partitions on the disk.
8. Initialize the swap partition on the new disk
9. If one of the arrays is inactive, must be restarted. Follow :[procedure for restarting]
10. Add the new partitions to existing arrays. Wait for the arrays to rebuild.
11. Mount the array and change the UUID of the swap partition in /etc/fstab
12. Rebuilding the boot system
12.1. Boot with Centos7 rescue image in troubleshooting mode
12.2. chroot to system, identify new disk, run grub2-install /dev/newdisk
13. If it worked one should see the grub boot – it might be required to boot again
If it didn't work the disk device at step 12.2 was wrong, repeat 12
Disk /dev/nvme0n1: 250.1 GB, 250059350016 bytes, 488397168 sectors Units = sectors of 1 * 512 = 512 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk label type: dos Disk identifier: 0x000c07b1 Device Boot Start End Blocks Id System /dev/nvme0n1p1 * 2048 195444735 97721344 fd Linux raid autodetect /dev/nvme0n1p2 195444736 390887423 97721344 fd Linux raid autodetect /dev/nvme0n1p3 390887424 422135807 15624192 82 Linux swap / Solaris Disk /dev/nvme1n1: 960.2 GB, 960197124096 bytes, 1875385008 sectors Units = sectors of 1 * 512 = 512 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk label type: dos Disk identifier: 0x000c4c4c Device Boot Start End Blocks Id System /dev/nvme1n1p1 * 2048 195444735 97721344 fd Linux raid autodetect /dev/nvme1n1p2 195444736 390887423 97721344 fd Linux raid autodetect /dev/nvme1n1p3 390887424 1875384319 742248448 fd Linux raid autodetect Disk /dev/nvme2n1: 960.2 GB, 960197124096 bytes, 1875385008 sectors Units = sectors of 1 * 512 = 512 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk label type: dos Disk identifier: 0x000e7acc Device Boot Start End Blocks Id System /dev/nvme2n1p1 * 2048 195444735 97721344 fd Linux raid autodetect /dev/nvme2n1p2 195444736 390887423 97721344 fd Linux raid autodetect /dev/nvme2n1p3 390887424 1875384319 742248448 fd Linux raid autodetect
:WIP: The machine will be monitored by a software and system monitor and an hardware monitor. Access and details to these systems will come.