Scratch Space

isginf operates a storage server for large scratch data that does not need backup.

Free

Research groups can request 2 TB of scratch storage for free with the option to increase to 5 TB if needed.

Shared Disks

Research groups with needs in the range 20 TB - 80TB can buy disk space in the shared pool.

Dedicated Disks

Research groups with large data needs (>= 100 TB) can buy disks for a dedicated pool. Disks are added to the system in groups of eight at once.

Disk to Disk Backup

Research group can buy twice the amount of space for shared or dedicated disks. The second half will be allocated in a georedundant backup server. Selected data in the scratch server will be replicated via snapshots to the space in the backup server.

Availability

The system needs to be booted from time to time to upgrade the operating system. This results in short outages. This is typically announced to the ITCs beforehand.

Data Safety

We use server-grade hardware that rarely fails and there is a cold spare to restore service in case of a hardware failure. The storage uses RAID 6 on groups of eight disks to make it resilient even to multiple hard drive failures. Snapshots of the file systems protect against accidental deletion.

Speed

The spinning disks allow only a limited amount of IOPS. For acceleration the metadata of files is written to NVME drives. Directory listings are fast but reading many files may be slow.

Backup

Access

Access to the shares can be through NFS4 with Kerberos or SMB/CIFS. NFS3 access is possible but requires separate shares.

Each group that uses this service usually has a share scratch that is available to all users of the group.

The available shares for each group are typically worked out with the groups ITC. The list of shares of your group on the scratch space along with the access policies can be found in the section with information for research groups.

Integration in isginf Linux Installations

On Linux installations managed by isginf the shares are accessible under /pub (via autofs), i.e., the scratch share is available under /pub/scratch.