BlueCrystal Phase 4 Storage¶

There are three main storage areas on BlueCrystal Phase 4:

Home directories

Scratch space

Purchased project space

Danger

None of these spaces are backed up. It is the user’s responsibility to ensure critical data are also on a backed-up area, for example the RDSF

Home Directories¶

Every user gets a home directory with a quota of 20 Gigabytes. This is for source code, application settings, submission scripts etc.

Scratch Space¶

There is also a larger space for each user (with quota of 512 Gigabytes) called “Scratch”. This is for large input and output datasets. This can be found under /mnt/storage/scratch/

If you find it easier you can create a convenience symlink in your home directory, e.g.:

ln -s /mnt/storage/scratch/$USER scratch

Checking your Quota¶

You can check your quota usage with the command mmlsquota

[mw16387@bc4login1 ~]$ mmlsquota --block-size auto
                         Block Limits                                               |     File Limits
Filesystem Fileset    type         blocks      quota      limit   in_doubt    grace |    files   quota    limit in_doubt    grace  Remarks
gpfs       root       USR         no limits
gpfs       home       USR          13.63G        19G        20G          0     none |   110793       0        0        0     none
gpfs       scratch    USR               0       510G       512G       320M     none |        2       0        0       38     none

The output is a bit confusing. Looking at the left hand block, your usage is in the “blocks” column. The quota column has the soft limit, once you go over that the clock starts ticking on the grace time. The “limit” column is the hard limit once you hit that you cannot write any more data in that space.

There is a line for each of the areas on the system, you can ignore the line for “root” that is an implementation detail.

The right hand half of the display concerns files, this is for information only as the quota is applied by the space used rather than the number of files (a quota of 0 indicates no limit).

Node Storage¶

The nodes are diskless and therefore the root filesystem is on RAM disk and consequently /tmp is on this ramdisk (Total Size including OS is 20G)

Purchased Project Space¶

Some groups have purchased extra space for their exclusive use. This is mounted under /mnt/storage/private. Your PI can tell you the name of the space you may have access to.

To enquire about purchasing space please email hpc-help@bristol.ac.uk

Permissions¶

The default permissions (since November 2017) are to allow user access but not group and others. E.g.

[username@bc4login1 ~]$ ls -ld ~
drwx------ 75 username grp 8192 Oct 31 14:05 /mnt/storage/home/username

You can change the permissions on a file or directory basis by using the chmod command. You can give members of your group or other additional permissions.