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Backups | ||||||||
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< < | The Nevis Linux cluster is backed up nightly onto shelley, the Nevis backup server. This includes the systems at the Nevis Annex. | |||||||
> > | The Nevis Linux cluster is backed up nightly onto shelley, the Nevis backup server. | |||||||
For speed, we don't copy every file from every system; we use a program called rsync![]() /home partition and /share partitions are backed up; /data is not. There is a web page that contains the list![]() | ||||||||
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< < | We maintain previous versions of old files on shelley. (Actually we do an incremental tar![]() ![]() | |||||||
> > | We maintain previous versions of old files on shelley. (Actually we do an incremental tar![]() ![]() | |||||||
Disk FAQ |
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Linux Cluster Disk Guide | ||||||||
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We don't back up every file on every system on the cluster. The policy is: the /home partition and /share partitions are backed up; /data is not. There is a web page that contains the list![]() | ||||||||
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< < | We maintain previous versions of old files on shelley. (Actually we do an incremental tar![]() ![]() | |||||||
> > | We maintain previous versions of old files on shelley. (Actually we do an incremental tar![]() ![]() | |||||||
Disk FAQ |
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We're doing what we can with the resources we have available. We don't have the disk space on our backup server for a year's worth of backups. | ||||||||
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> > | /data disk. That way, when my home directory is backed up --
Stop right there. It won't work. The backup procedure does not follow links. We've had at least one student who lost critical files because they tried this trick. You can't magically increase your available backed-up disk space in this way.
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![]() ~seligman/bin/rsync.sh on the Linux cluster. |
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Linux Cluster Disk Guide | ||||||||
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< < | This is a guide to issues with disk storage on the on the Linux cluster. To find out how disks on one system can be accessed from another, see the automount page. To understand different partition names (e.g., why are there /share and /scratch directories), see the disk sharing page.
The most important thing to learn from this page is that /home and /share partitions are backed up. /data and /scratch are not. Read the rest of this page to understand why and what you can do about this. | |||||||
> > | The most important things to learn from this page:
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How much disk space do I have? |
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This is a guide to issues with disk storage on the on the Linux cluster. To find out how disks on one system can be accessed from another, see the automount page. To understand different partition names (e.g., why are there /share and /scratch directories), see the disk sharing page. | ||||||||
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> > | The most important thing to learn from this page is that /home and /share partitions are backed up. /data and /scratch are not. Read the rest of this page to understand why and what you can do about this. | |||||||
How much disk space do I have?To find out how much disk space you have available, use the df![]() -h option, so the sizes appear in human-readable form: |
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We don't back up every file on every system on the cluster. The policy is: the /home partition and /share partitions are backed up; /data is not. There is a web page that contains the list![]() | ||||||||
Changed: | ||||||||
< < | We maintain previous versions of old files on shelley. (Actually we do an incremental tar![]() ![]() | |||||||
> > | We maintain previous versions of old files on shelley. (Actually we do an incremental tar![]() ![]() | |||||||
Disk FAQ |
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Linux Cluster Disk Guide | ||||||||
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We don't back up every file on every system on the cluster. The policy is: the /home partition and /share partitions are backed up; /data is not. There is a web page that contains the list![]() | ||||||||
Changed: | ||||||||
< < | We maintain previous versions of old files on shelley. (Actually we do an incremental tar![]() ![]() | |||||||
> > | We maintain previous versions of old files on shelley. (Actually we do an incremental tar![]() ![]() | |||||||
Disk FAQ |
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Linux Cluster Disk Guide | ||||||||
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What do I do if I need more disk space? | ||||||||
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< < | First, look to /data partitions on other systems in your working group. The /data partitions on all the systems that belong to a group are intended to be a shared resource; if you don't have enough space on /a/data/yourmachine , cd /a/data/othermachine in your group and see how much free space it has. | |||||||
> > | First, look to /data partitions on other systems in your working group. The /data partitions on all the systems that belong to a group are intended to be a shared resource; if you don't have enough space on /nevis/yourmachine/data , cd /nevis/othermachine/data in your group and see how much free space it has. | |||||||
I strongly advise you to exercise common courtesy as you're scrounging for disk space. If I found someone had used a big chunk of my server's /data partition without asking, I might be annoyed. | ||||||||
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I run this script automatically a few times per day using cron![]() ![]() | ||||||||
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< < | 10 */6 * * * /a/home/tanya/seligman/bin/rsync.sh | |||||||
> > | 10 */6 * * * /nevis/tanya/home/seligman/bin/rsync.sh | |||||||
This translates to: Every six hours, at ten minutes past the hour, run my script. |
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> > |
Linux Cluster Disk Guide/share and /scratch directories), see the disk sharing page.
How much disk space do I have?To find out how much disk space you have available, use the df![]() -h option, so the sizes appear in human-readable form:
df -hYou'll almost certainly see disks in the list that are mounted via automount. If you find the automounted disks to be distracting, add -l to the command:
df -hlBear in mind that you don't want to use the -l option if your home directory is not on the machine to which you've logged in. (As of Jan-2017, this mainly applies to ATLAS users logged onto xenia .)
Here's the result of executing df -hl on the machine tanya on 28-Jan-2017:
Filesystem Size Used Avail Use% Mounted on /dev/mapper/VG-root 20G 9.2G 9.5G 50% / tmpfs 494M 760K 493M 1% /dev/shm /dev/md0 461M 98M 340M 23% /boot /dev/mapper/VG-home 50G 16G 32G 33% /home /dev/mapper/VG-data 222G 6.1G 205G 3% /dataIf we ignore partitions that relate to the operating system, we're left with two key user-accessible filesystems: /home and /data . (Many systems have other key partitions, such as /share and /scratch .)
It's not muchYour first reaction may be: "There's not much disk space for my home directory, and I have to share that space with other people in the collaboration. Why, my watch has more storage than that!" You're right. It's intended that the/home be used for "source" files (program code, scientific papers, plots, etc.); /data or /scratch should be used for large and re-creatable files (compiled binaries, data summaries, temporary work files, etc.). We have to ask you to use judgement and discipline, and to be aware that you're sharing space with your fellow scientists.
If you're just skimming this page, stop and read thisThe reason why/home is small and /data is big is that the /home partition is backed up; /data is not. In fact, it goes one step further: the /data partition is always considered expendable for any type of system maintenance activity. If a system is being repaired, upgraded, or restored, the /data partition may be erased.
There's more about this in the section on backups below.
What do I do if I need more disk space?First, look to/data partitions on other systems in your working group. The /data partitions on all the systems that belong to a group are intended to be a shared resource; if you don't have enough space on /a/data/yourmachine , cd /a/data/othermachine in your group and see how much free space it has.
I strongly advise you to exercise common courtesy as you're scrounging for disk space. If I found someone had used a big chunk of my server's /data partition without asking, I might be annoyed.
If you still don't have enough disk space on all your group's machines to satisfy your needs, you may have to request more disks be added to the existing systems (or buy a new box).
BackupsThe Nevis Linux cluster is backed up nightly onto shelley, the Nevis backup server. This includes the systems at the Nevis Annex. For speed, we don't copy every file from every system; we use a program called rsync![]() /home partition and /share partitions are backed up; /data is not. There is a web page that contains the list![]() ![]() ![]() Disk FAQ
Long-term data storageFor the purposes of this section, "long-term" means more than six months or so. By the above definition, there is no long-term data storage at Nevis. As noted above:
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