System - Revision history

GiulioFontana: /* How to find out who is using a shared storage space */

2026-06-08T09:54:04Z

How to find out who is using a shared storage space

← Older revision		Revision as of 09:54, 8 June 2026
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	</pre>		</pre>

	to see a list of its contents with size and owner of each item. This ~~way~~ you ~~can~~ know who to ask if you need ~~more space than currently available, to see if they are able~~ to delete some files to make space for other users.		to see a list of its contents with size and owner of each item.

			This allows you to know who to ask if you need someone to delete some some files to make space for other users. Shared directories are shared spaces, and files should never be left there for longer than strictly necessary; however, sometimes one forgets :-)

	== Disk quotas ==		== Disk quotas ==

GiulioFontana: /* How to find out who is using a shared storage space */

2026-06-08T09:51:53Z

How to find out who is using a shared storage space

← Older revision		Revision as of 09:51, 8 June 2026
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	</pre>		</pre>

	to see a list of its contents with ~~their owners~~ and ~~their size~~. This way you can know who to ask if you need more space than currently available, to see if they are able to delete some files to make space for other users.		to see a list of its contents with size and owner of each item. This way you can know who to ask if you need more space than currently available, to see if they are able to delete some files to make space for other users.

	== Disk quotas ==		== Disk quotas ==

GiulioFontana: /* Using Mufasa */

2026-06-08T09:51:22Z

Using Mufasa

← Older revision		Revision as of 09:51, 8 June 2026
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	::: '''Important!''' Shared directories are used by several people, so it's important to ''quickly remove from them any file that is not actively in use''.		::: '''Important!''' Shared directories are used by several people, so it's important to ''quickly remove from them any file that is not actively in use''.

	To know how space is available in a shared directory ~~(that you have access to)~~ and how much of such space is currently in use, you can use command		To know how space is available in a shared directory and how much of such space is currently in use, you can use command

	<pre style="color: lightgrey; background: black;">		<pre style="color: lightgrey; background: black;">
	df -h <path of shared directory>		df -h <path of shared directory>
	</pre>		</pre>

			=== How to find out who is using a shared storage space ===
			If you have access to a shared directory, you can use

			<pre style="color: lightgrey; background: black;">
			ls -l <path to shared directory>
			</pre>

			to see a list of its contents with their owners and their size. This way you can know who to ask if you need more space than currently available, to see if they are able to delete some files to make space for other users.

	== Disk quotas ==		== Disk quotas ==

GiulioFontana: /* Storage spaces */

2026-06-08T09:45:51Z

Storage spaces

← Older revision		Revision as of 09:45, 8 June 2026
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	::: ''Mufasa is not a storage space!''		::: ''Mufasa is not a storage space!''

	To know how space is available in your personal directory and how much of it is in use, you can use command		To know how space is available in your personal directory and how much of that space is currently in use, you can use command

	<pre style="color: lightgrey; background: black;">		<pre style="color: lightgrey; background: black;">
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	::: '''Important!''' Shared directories are used by several people, so it's important to ''quickly remove from them any file that is not actively in use''.		::: '''Important!''' Shared directories are used by several people, so it's important to ''quickly remove from them any file that is not actively in use''.

	To know how space is available in ~~your research group's~~ shared directory and how much of it is in use, you can use command		To know how space is available in a shared directory (that you have access to) and how much of such space is currently in use, you can use command

	<pre style="color: lightgrey; background: black;">		<pre style="color: lightgrey; background: black;">

GiulioFontana: /* Storage spaces */

2026-06-08T09:45:04Z

Storage spaces

← Older revision		Revision as of 09:45, 8 June 2026
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	To know how space is available in your personal directory and how much of it is in use, you can use command		To know how space is available in your personal directory and how much of it is in use, you can use command

			<pre style="color: lightgrey; background: black;">
			df -h ~
			</pre>

	:; Shared directories		:; Shared directories
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	::: - For '''faster read/write'''. Shared spaces are physically located on faster disks wrt the personal home directories (SSDs instead of mechanical HDDs). When a processing job requires reading or writing very large amounts of data, placing such data in a shared directory can significantly speed up the job.		::: - For '''faster read/write'''. Shared spaces are physically located on faster disks wrt the personal home directories (SSDs instead of mechanical HDDs). When a processing job requires reading or writing very large amounts of data, placing such data in a shared directory can significantly speed up the job.
	::: '''Important!''' Shared directories are used by several people, so it's important to ''quickly remove from them any file that is not actively in use''.		::: '''Important!''' Shared directories are used by several people, so it's important to ''quickly remove from them any file that is not actively in use''.
	~~::: See [[#Finding out~~ how ~~much disk~~ space is ~~used by a~~ directory~~\|Finding out~~ how much ~~disk space~~ is ~~used by a~~ directory~~]] to know how to check for available space.~~
			To know how space is available in your research group's shared directory and how much of it is in use, you can use command

			<pre style="color: lightgrey; background: black;">
			df -h <path of shared directory>
			</pre>

	== Disk quotas ==		== Disk quotas ==

GiulioFontana: /* Storage spaces */

2026-06-08T09:43:15Z

Storage spaces

← Older revision		Revision as of 09:43, 8 June 2026
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	::: The general rule is: ''keep in your home directory '''only''' the files that the work you are doing on Mufasa '''right now''' needs; remove a file as soon as it is not needed anymore for your current work''.		::: The general rule is: ''keep in your home directory '''only''' the files that the work you are doing on Mufasa '''right now''' needs; remove a file as soon as it is not needed anymore for your current work''.
	::: ''Mufasa is not a storage space!''		::: ''Mufasa is not a storage space!''
	~~::: See [[#Finding out~~ how ~~much disk~~ space is ~~used by a~~ directory~~\|Finding out~~ how much ~~disk space~~ is ~~used by a directory]] to know how to check for available space.~~
			To know how space is available in your personal directory and how much of it is in use, you can use command




	:; Shared directories		:; Shared directories

GiulioFontana: /* Storage spaces */

2026-06-08T09:39:12Z

Storage spaces

← Older revision		Revision as of 09:39, 8 June 2026
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	::: The general rule is: ''keep in your home directory '''only''' the files that the work you are doing on Mufasa '''right now''' needs; remove a file as soon as it is not needed anymore for your current work''.		::: The general rule is: ''keep in your home directory '''only''' the files that the work you are doing on Mufasa '''right now''' needs; remove a file as soon as it is not needed anymore for your current work''.
	::: ''Mufasa is not a storage space!''		::: ''Mufasa is not a storage space!''
			::: See [[#Finding out how much disk space is used by a directory\|Finding out how much disk space is used by a directory]] to know how to check for available space.

	:; Shared directories		:; Shared directories
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	::: - For '''faster read/write'''. Shared spaces are physically located on faster disks wrt the personal home directories (SSDs instead of mechanical HDDs). When a processing job requires reading or writing very large amounts of data, placing such data in a shared directory can significantly speed up the job.		::: - For '''faster read/write'''. Shared spaces are physically located on faster disks wrt the personal home directories (SSDs instead of mechanical HDDs). When a processing job requires reading or writing very large amounts of data, placing such data in a shared directory can significantly speed up the job.
	::: '''Important!''' Shared directories are used by several people, so it's important to ''quickly remove from them any file that is not actively in use''.		::: '''Important!''' Shared directories are used by several people, so it's important to ''quickly remove from them any file that is not actively in use''.
			::: See [[#Finding out how much disk space is used by a directory\|Finding out how much disk space is used by a directory]] to know how to check for available space.

	== Disk quotas ==		== Disk quotas ==

GiulioFontana at 10:41, 3 February 2026

2026-02-03T10:41:15Z

← Older revision		Revision as of 10:41, 3 February 2026
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	This section provide a brief guide to Mufasa users (especially those who are not experienced in the use of Linux and/or remote servers) about interacting with the system.		This section provide a brief guide to Mufasa users (especially those who are not experienced in the use of Linux and/or remote servers) about interacting with the system.

	== ~~<span style="background:#FFFF00">~~Storage spaces~~</span>~~ ==		== Storage spaces ==

	User jobs require storage of programs and data files. On Mufasa, the space available to users for data storage is the <code>/home/</code> directory. <code>/home/</code> contains two types of directories:		User jobs require storage of programs and data files. On Mufasa, the space available to users for data storage is the <code>/home/</code> directory. <code>/home/</code> contains two types of directories:
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	::: '''Important!''' Shared directories are used by several people, so it's important to ''quickly remove from them any file that is not actively in use''.		::: '''Important!''' Shared directories are used by several people, so it's important to ''quickly remove from them any file that is not actively in use''.

	== ~~<span style="background:#FFFF00">~~Disk quotas~~</span>~~ ==		== Disk quotas ==

	In Mufasa, [[#Storage spaces\|Storage spaces]] are subjected to quotas: i.e., the files that are stored in them cannot occupy more than a given amount of disk space. Quotas apply both to personal directories (e.g., <code>/home/userX/</code>) and to shared directories (e.g., <code>/home/shared/ResearchGroupY/</code>).		In Mufasa, [[#Storage spaces\|Storage spaces]] are subjected to quotas: i.e., the files that are stored in them cannot occupy more than a given amount of disk space. Quotas apply both to personal directories (e.g., <code>/home/userX/</code>) and to shared directories (e.g., <code>/home/shared/ResearchGroupY/</code>).
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	If you want additional information about file and directory permissions in a Linux system work, [https://www.redhat.com/sysadmin/linux-file-permissions-explained this is a good online guide].		If you want additional information about file and directory permissions in a Linux system work, [https://www.redhat.com/sysadmin/linux-file-permissions-explained this is a good online guide].

	= ~~<span style="background:#ffff00">~~Containers~~</span>~~ =		= Containers =

	[[File:Singularity.png\|right\|262px]]		[[File:Singularity.png\|right\|262px]]

GiulioFontana at 10:39, 3 February 2026

2026-02-03T10:39:59Z

← Older revision		Revision as of 10:39, 3 February 2026
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	Remote access to Mufasa is performed using the [[System#Accessing Mufasa\|SSH protocol]] for the execution of commands and the [[System#File transfer\|SFTP protocol]] for the exchange of files. Once logged in, a user interacts with Mufasa via a terminal (text-based) interface.		Remote access to Mufasa is performed using the [[System#Accessing Mufasa\|SSH protocol]] for the execution of commands and the [[System#File transfer\|SFTP protocol]] for the exchange of files. Once logged in, a user interacts with Mufasa via a terminal (text-based) interface.

	= ~~<span style="background:#ffff00">~~Mufasa 2.0~~</span>~~ =		= Mufasa 2.0 =

	At the beginning of November 2025 Mufasa has been subjected to a comprehensive hardware and software overhaul: the new system is sometimes called '''Mufasa 2.0'''; to distinguish it from the old system, the latter is sometimes called "Mufasa 1.0".		At the beginning of November 2025 Mufasa has been subjected to a comprehensive hardware and software overhaul: the new system is sometimes called '''Mufasa 2.0'''; to distinguish it from the old system, the latter is sometimes called "Mufasa 1.0".

	This wiki ~~is currently (November 2025) being~~ updated to reflect the changes. Elements that changed significantly from Mufasa 1.0 to Mufasa 2.0 are <span style="background:#ffff00">highlighted in yellow</span>. When the title of a section is highlighted, it means either that it is a new section, or that the section's contents significantly changed.		This wiki has been updated to reflect the changes.

	= Hardware =		= Hardware =
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	* 2 AMD Epyc 7542 32-core processors (64 CPU cores total)		* 2 AMD Epyc 7542 32-core processors (64 CPU cores total)
	* 1 TB RAM		* 1 TB RAM
	* 7 TB of SSDs ~~<span style="background:#ffff00">~~(fast temporary repository for datasets actively being used - see [[#Storage spaces\|Storage spaces]])~~</span>~~		* 7 TB of SSDs (fast temporary repository for datasets actively being used - see [[#Storage spaces\|Storage spaces]])
	* 25 TB of HDDs (for user <code>/home</code> directories)		* 25 TB of HDDs (for user <code>/home</code> directories)
	* ~~<span style="background:#ffff00">~~8 Nvidia A100 GPUs~~</span>~~ [based on the ''Ampere'' architecture]		* 8 Nvidia A100 GPUs [based on the ''Ampere'' architecture]
	* [https://ubuntu.com/ Ubuntu Linux 24.04 LTS server] operating system		* [https://ubuntu.com/ Ubuntu Linux 24.04 LTS server] operating system

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	All in all, the GPU complement of Mufasa comprises the following devices:		All in all, the GPU complement of Mufasa comprises the following devices:

	:; ~~<span style="background:#FFFF00">~~5 GPUs with 20GB of RAM and 3 compute units~~</span>~~		:; 5 GPUs with 20GB of RAM and 3 compute units
	:; ~~<span style="background:#FFFF00">~~5 GPUs with 20GB of RAM and 4 compute units~~</span>~~		:; 5 GPUs with 20GB of RAM and 4 compute units
	:; ~~<span style="background:#FFFF00">~~3 GPUs with 40 GB of RAM~~</span>~~		:; 3 GPUs with 40 GB of RAM

	Thanks to MIG, users can use all the GPUs listed above as if they were all physical devices installed on Mufasa, without having to worry (or even know) which actually are and which instead are virtual GPUs. How these devices are made available to Mufasa users is explained in [[SLURM]].		Thanks to MIG, users can use all the GPUs listed above as if they were all physical devices installed on Mufasa, without having to worry (or even know) which actually are and which instead are virtual GPUs. How these devices are made available to Mufasa users is explained in [[SLURM]].
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	= Accessing Mufasa =		= Accessing Mufasa =

	== ~~<span style="background:#ffff00">~~Login server~~</span>~~ ==		== Login server ==

	Differently from Mufasa 1.0, Mufasa 2.0 employs a ''login server'' to manage user connections. The login server is a Linux virtual machine with very limited resources (no GPUs, few CPUs, small RAM). Its task is only to provide users with a way to log into the system and launch [[User Jobs]] with SLURM. Jobs launched via SLURM run on Mufasa 2.0's physical hardware (not on the virtual hardware of the login server) and therefore can access to the hardware resources of Mufasa, such as the GPUs.		Differently from Mufasa 1.0, Mufasa 2.0 employs a ''login server'' to manage user connections. The login server is a Linux virtual machine with very limited resources (no GPUs, few CPUs, small RAM). Its task is only to provide users with a way to log into the system and launch [[User Jobs]] with SLURM. Jobs launched via SLURM run on Mufasa 2.0's physical hardware (not on the virtual hardware of the login server) and therefore can access to the hardware resources of Mufasa, such as the GPUs.
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	Please note that if you try to run computationally heavy processes in the login server you can easily overwhelm its scarce resources, making it unavailable to all users and thus making Mufasa unreachable by anyone. The login server has safety mechanisms to prevent processes from hogging too much of its resources... by killing such processes. However, please avoid checking if these mechanisms work.		Please note that if you try to run computationally heavy processes in the login server you can easily overwhelm its scarce resources, making it unavailable to all users and thus making Mufasa unreachable by anyone. The login server has safety mechanisms to prevent processes from hogging too much of its resources... by killing such processes. However, please avoid checking if these mechanisms work.

	== ~~<span style="background:#ffff00">~~Logging into the login server~~</span>~~ ==		== Logging into the login server ==

	User access to Mufasa is always remote and exploits the ''SSH'' (''Secure SHell'') protocol.		User access to Mufasa is always remote and exploits the ''SSH'' (''Secure SHell'') protocol.
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	from the command prompt of the remote shell.		from the command prompt of the remote shell.

	== ~~<span style="background:#ffff00">~~Direct access to Mufasa (for users with running SLURM jobs)~~</span>~~ ==		== Direct access to Mufasa (for users with running SLURM jobs) ==

	While a user has SLURM jobs in execution, such user may also log into Mufasa directly, without passing through the login server. This allows the user to interact with the running jobs, e.g. to monitor their progress. Direct access to Mufasa is done via SSH with command		While a user has SLURM jobs in execution, such user may also log into Mufasa directly, without passing through the login server. This allows the user to interact with the running jobs, e.g. to monitor their progress. Direct access to Mufasa is done via SSH with command

GiulioFontana: /* Disk quotas */

2026-02-03T10:17:51Z

Disk quotas

← Older revision		Revision as of 10:17, 3 February 2026
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	</pre>		</pre>

	When <code>df</code> is run from the is [[#Logging into the login server\|login server]], its output is similar to the following:		When <code>df</code> is run from the is [[#Logging into the login server\|login server]], its output is similar to the following, respectively for a home directory and a shared space:

	<pre style="color: lightgrey; background: black;">		<pre style="color: lightgrey; background: black;">
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	Filesystem Size Used Avail Use% Mounted on		Filesystem Size Used Avail Use% Mounted on
	192.168.1.1:/home 200G 161G 40G 81% /home		192.168.1.1:/home 200G 161G 40G 81% /home
			</pre>

			<pre style="color: lightgrey; background: black;">
			gfontana@mufasa2-login:~$ df -h /home/shared/nearmrs/
			Filesystem Size Used Avail Use% Mounted on
			192.168.1.1:/mnt/shared 1.3T 1008G 293G 78% /mnt/shared
	</pre>		</pre>