The Petastore file system is in the process of being removed from service and will be decommissioned before 2024. Any data currently stored on the Petastore file system needs to be immediately copied off and saved. If you require assistance with this or would like to discuss further options, please contact circ-assist@utdallas.edu.

Petastore

Petastore, the Parallel File System for the CIRC cluster Ganymede, is a 1.2 PB IBM General Parallel File System (GPFS) storage appliance that provides dedicated storage as well as user scratch space.

Hardware

Petastore consists of 3 main components: the network fabric, the filers, and the disk arrays. The network fabric is a 100 gigabit/s Infiniband network with redundant links between two Mellanox EDR (100 gigabit/s) switches. The filers are two standard servers, each with redundant links between the switches and the disk arrays. These servers are the actual exporters of the filesystem as well as control systems. The DataDirect Networks (DDN) disk arrays (3 in this case) are filled with spinning disks as well as a number of SSD cache/metadata drives.

On Ganymede

Petastore exports to Ganymede as /petastore, but is generally user-accessible as ~/scratch. On the cluster side:

Directory Filesystem Type Network Speed Filesystem Size User Quota (Soft/Hard) Backup Frequency

~/scratch (via /petastore)

40/56/100 gigabit/s[1]

IBM General Parallel File System

1.2 PB

None

None

Please notate in the preceding chart that ~/scratch is NOT BACKED UP IN ANY FORM OR FASHION. Any important data should NOT be stored on the Ganymede Scratch filesystem. Important data should be stored in your home directory, or if applicable, your MooseFS /work directory. While we generally ask users to voluntarily clean up ~/scratch, we reserve the right to purge scratch at any time. If you need assistance, please email circ-assist@utdallas.edu.

In addition to the free-to-everyone scratch space, some groups have opted to buy in to the Petastore system (generally to fund the purchase of disks and/or enclosures). If you believe your research group is included in this category, please email circ-assist@utdallas.edu for more information and assistance.

Usage

On Ganymede, ~/scratch is best utilized for high I/O and "larger than 20 GB" datasets, TEMPORARILY. Please utilize the scratch space as "copy to, run, clean up when done" space. The filesystem is a shared resource amongst all Ganymede users and needs to be kept as clean as possible for performance and usability reasons.

Note the network speeds are 40/56/100 gigabit/s rather than Base10 (10/100/1000 M). This is due to the network link being Infiniband as opposed to Ethernet; Infiniband is a much faster and much lower latency (0.5 us as opposed to 5-10 ms) than Ethernet. This allows much faster file access (near-instantaneous) when running jobs and ~1.3 GB/s file read/write, which is about 10 times faster than the "standard" link to Ganymede’s /home. Also, due to its parallel nature, the filesystem doesn’t get saturated as easily as /home, which allows more users to run jobs at the same time. MPI jobs are no issue for ~/scratch, so it’s highly advised to use that space for running jobs, whether parallel or serial.

If you need persistent data storage in addition to the temporary scratch space, please contact circ-assist@utdallas.edu with the amount of storage you need, how long you need it, and what your workloads are and a CIRC team member will work with you to determine how best to proceed.

Backups

Recall from above, ~/scratch is NOT BACKED UP. Repeat, the entire Petastore filesystem is NOT BACKED UP. The logistics of backing up 1.2 PB of data make it extremely difficult and cost-ineffective to retain any backups. Any data on Petastore can be considered as volatile, so if it’s important please move it off when your job is complete. The hardware running the storage is robust, but nothing is invincible so please be cautious with data storage.

Cleanup

As Petastore is a shared resource by many, we ask that everyone cleans up their data when their jobs have finished, they no longer need it, or if it’s been copied to an external file system. Often times, Petastore will reach +90% utilization and we will send out an notification for users to clean up what they can to keep the filesystem performing optimally. This has continued to work when we’ve asked so automated purge policies haven’t been implemented, but the file system does support implementation of said policies.

1. The `smallmem` queue utilizes a 40 gigabit/s link whereas the `normal` and `debug` queues utilize a 56 gigabit/s link. Some privately accessible nodes utilize a 100 gigabit/s link. The storage appliance itself exports the filesystem at 100 gigabit/s.