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services:computing:hpc [2021/05/24 15:06] calucci filesystems & backups |
services:computing:hpc [2022/02/11 15:20] calucci email reports |
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| - | Ulysses v2 can be accessed via the login nodes at ''frontend1.hpc.sissa.it'' or ''frontend2.hpc.sissa.it'' from SISSA network or from SISSA [[:vpn|VPN]]. More access options might be made available in due time. | + | SSH access to Ulysses v2 is provided via the login nodes at ''frontend1.hpc.sissa.it'' or ''frontend2.hpc.sissa.it'' from SISSA network or from SISSA [[:vpn|VPN]]. More access options might be made available in due time. |
| ===== Hardware and Software ===== | ===== Hardware and Software ===== | ||
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| The software tree is the same you have on Linux workstations, with the same [[services:modules|Lmod modules]] system (with the only exception of desktop-oriented software packages). | The software tree is the same you have on Linux workstations, with the same [[services:modules|Lmod modules]] system (with the only exception of desktop-oriented software packages). | ||
| + | |||
| + | A small number of POWER9-based nodes are also available (2 sockets, 16 cores, 4 threads per core; 256GB RAM) with 2 or 4 Tesla V100. Please note that you cannot run x86 code on POWER9. For an interactive shell on a P9 machine, please type ''p9login'' on frontend[12]. | ||
| ===== Queue System ===== | ===== Queue System ===== | ||
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| * **''long1''** and **''long2''**: max 8 nodes, max 48h | * **''long1''** and **''long2''**: max 8 nodes, max 48h | ||
| * **''gpu1''** and **''gpu2''**: max 4 nodes, max 12h | * **''gpu1''** and **''gpu2''**: max 4 nodes, max 12h | ||
| + | * **''power9''**: max 2 nodes, max 24h | ||
| <note tip>Please note that hyperthreading is enabled on all nodes (it was disabled on old Ulysses). If you **do not** want to use hyperthreading, the ''%%--hint=nomultithread%%'' options to srun/sbatch will help. | <note tip>Please note that hyperthreading is enabled on all nodes (it was disabled on old Ulysses). If you **do not** want to use hyperthreading, the ''%%--hint=nomultithread%%'' options to srun/sbatch will help. | ||
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| </code> | </code> | ||
| + | <note warning>Please note that MPI jobs are only supported if they allocate all available core/threads on each node (so 20c/40t on *1 partitions and 32c/64t on *2 partitions. In this context, //not supported// means that jobs using fewer cores/threads than available may or may not work, depending on how cores //not// allocated to your job are used.</note> | ||
| ===== Filesystem Usage and Backup Policy ===== | ===== Filesystem Usage and Backup Policy ===== | ||
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| Due to their inherent volatility, some directories can be excluded from the backup set. At this time, the list of excluded directories includes only one item, namely ''/home/$USER/.cache'' | Due to their inherent volatility, some directories can be excluded from the backup set. At this time, the list of excluded directories includes only one item, namely ''/home/$USER/.cache'' | ||
| + | |||
| + | ===== Job E-Mail ===== | ||
| + | You can enable e-mail notifications at various stages of each job life with the ''--mail-type=TYPE'' option where ''TYPE'' can be a comma-separated list such as ''BEGIN,END,FAIL'' (more details are available in ''man sbatch''). Notification recipient is by default your SISSA e-mail address, but you can select a different address with ''--mail-user''. **End-job** notification includes a summary of consumed resources (CPU time and memory) as absolute values and as a percentage of requested resources. Please note that memory usage is sampled at 30 seconds intervals, so if your job is terminated by an out-of-memory condition arising from a very large failed allocation, the reported value can be grossly underestimated. | ||
| + | ==== Energy Accounting ==== | ||
| + | An experimental energy accounting system has been enabled on Ulysses, and energy usage estimates are reported in end-job notification. This is intended as a very rough estimate of the energy impact your job has, but is **not** accurate enough to be used for proper cost/energy/environmental accounting. Known limits of the energy accounting system in use include: | ||
| + | * very small values are completely unreliable (and are not included at all in the end-job notification, so in case of very short or "mostly idle" job you will find no value at all) | ||
| + | * only CPU and memory energy usage are considered, while energy consumed by other devices (network cards, disk controllers, service processors, power supplies) is not accounted for; energy used "outside" the compute nodes is not considered as well (this include network devices, external storage, UPS, HVAC), so even for a CPU-intensive job the "real" energy consumption can easily be twice as much than reported | ||
| + | * on the other side, //if your job doesn't use all available cores on each allocated node//, energy consumption can be overestimated | ||
| ===== Reporting Issues ===== | ===== Reporting Issues ===== | ||
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| When reporting issues with Ulysses, please keep to the following guidelines: | When reporting issues with Ulysses, please keep to the following guidelines: | ||
| - | * write to [[helpdesk-hpc@sissa.it]], not to personal email addresses: this way your enquiry will be seen by more than one person | + | * write to [[helpdesk-hpc@sissa.it]], not to personal email addresses: this way your request will be seen by more than one person |
| * please use a clear and descriptive subject for your message: "missing library libwhatever.so.12 from package whatever-libs" is OK, "missing software" is less useful, "Ulysses issues" is definitely not useful | * please use a clear and descriptive subject for your message: "missing library libwhatever.so.12 from package whatever-libs" is OK, "missing software" is less useful, "Ulysses issues" is definitely not useful | ||
| * please open one ticket for each issue; **do not** reply to old, closed tickets for unrelated issues | * please open one ticket for each issue; **do not** reply to old, closed tickets for unrelated issues | ||