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Best Practice for Use of the HFS

1. Introduction

The following recommendations give advice on how to get the best use of the HFS backup service.

2. Limit what you back up

2.1. Only back up what you need to back up

The fewer files that you select for backup, the quicker your backup will be, and the less you will use the university resources involved in sending your data to the HFS and in keeping it stored there. You are also more likely to notice any problems with your backups (such as files failing to be backed up) if you keep your backups to a manageable size.

  • If you are only running manual backups, please see our instructions on how to select only certain files for backup in our instructions on running a manual backup in Windows, Mac and Linux.
  • Use the exclude rules in the backup software to exclude from backup anything that you do not need or do not want to send: this will prevent such data being sent to the HFS accidentally. If you leave your machine switched on and it runs a scheduled backup, the backup software will back up all the data that it can from any drives that are attached to your machine, as well as your main drive. So, if necessary, exclude from backup any drives that you do not want to back up, e.g. ones that duplicate data that is on your main drive, using our instructions for excluding drives and partitions from backup. Then exclude any other data that you do not wish to back up, which might include temporary files and non-work related data, by using our instructions for excluding files and folders; or if you have only a limited data set to back up then exclude everything from backup except specific files or folders.

2.2. Only back up your work

The HFS is intended for the backup of your university-related work. So, whilst we understand that hard drives may contain a combination of both work and personal data, please try to exclude from backup your non-work files, using the instructions mentioned in the previous section. This is particularly important in the case of copyrighted material such as music and movies, which can take up a substantial amount of hard drive space. We already exclude certain files from backup, most notably temporary files and virtual machines - on this please see further our page on files and folders excluded from backup.

3. Check that your backups are working

For all accounts except those registered for manual backup only, e-mails are sent out if a scheduled backup fails to run correctly. However these mails are only a guide, and the absence of a scheduled backup failure report does not guarantee that every single file has been backed up. We therefore recommend that you verify that your backups are running as intended.

  • For how to check that your backups are running correctly, please see our page on how to check that backups ran successfully.
  • If you have received an e-mail from us, please respond promptly:
    • A scheduled backup failure report, depending on its contents, indicates that your backup either did not start (i.e. it is classed as missed), or did start but failed to complete (in which case it is classed as severed or failed).
    • An HFS backup cancellation report will mean that your backup session was cancelled as it broke one of our limits: duration, slow speed, or quantity. In the latter case, unless your account has been registered within the preceding 14 days, backups for your account will be suspended until you contact us.
    • A mail headed Old data on the HFS means that some part of your data has not been backed up recently and that it could therefore become a candidate for deletion.

4. Avoid making large-scale changes to your computer or your data

Sometimes making large-scale changes to your computer is unavoidable. Please bear in mind, though, that such changes may affect your backups. The lists below cover the most common types.

4.1. Changes that cause the HFS backup software to resend data to the HFS

There are several sets of circumstances in which the backup client software can be inadvertently prompted to resend data unnecessarily. If you find that you have made changes of the sort listed below, then your HFS account may get locked because you sent more than the daily backup limit allows. To avoid this, stop your backup scheduler and run manual backups, keeping within the daily limits until your backups complete again. For how to stop the backup scheduler, please see our instructions for Windows, Mac, Linux. and Solaris. For how to keep within the daily limit and so avoid your account getting locked, see our FAQ item How can I limit the amount of data that I'm backing up?.

  • Renaming your machine - in Windows, TSM stores data by UNC path, which means that e.g. on a PC called my-laptop, C: would be represented as \\my-laptop\c$, D: as \\my-laptop\d$, and so on. Renaming a Windows machine changes that path, causing a complete resend of data under the new path - e.g. \\my-renamed-laptop\c$, \\my-renamed-laptop\d$. So please avoid renaming your machine unless absolutely necessary, and if you do have to then please e-mail us at Please note that this is only true of Windows: renaming Mac and Linux machines causes no such problem.
  • Changing drive names or drive letters - similarly, changing a drive name will cause a resend of data from that drive. All data on a Mac external drive renamed from /Volumes/my-external-drive to /Volumes/my-renamed-external-drive would be resent by the HFS backup software. In Windows, take care not to vary the order in which you attach any extra drives - Windows will assign them different letters if you change the order, so you might find that the backup client resends the data that you backed up from E: again from F:, as if F: were a different drive.
  • Moving, renaming, or changing permissions on data - this will generally also cause the client to resend that data. If you have a folder called data and you rename it to e.g. old-data then the backup client software will regard it as new and resend the entire contents of that folder, including all sub-folders. Changes of permissions usually also occasion resends. We therefore request that large-scale changes to your data be avoided unless absolutely necessary.

4.2. Other changes

There are other changes that are system-wide but which generally do not cause a resend of your data, but which can have other unforeseen consequences - these are listed below.

  • Changing operating system by upgrading an existing machine - if you intend to upgrade an existing machine then please go to our page on downloading the software for the IT Services HFS backup service to upgrade TSM to the correct version for your new operating system.
    • If your new operating system is not listed on that page, we would recommend that you delay upgrading, if possible, until a supported version of the backup client software is released. HFS accounts seen to be using an unsupported operating system will be locked, and their contents preserved, until the relevant client software version is available. Please note that we do not support beta or release candidate operating systems.
    • If your new operating system is listed, please upgrade the backup client software immediately after you have upgraded your operating system. This is because new versions of the backup software do not support older operating systems, so if you upgrade from (say) Windows 7 to 10, or from Mac OS X 10.10 to 10.11, then you may find that your existing version of the HFS backup software is no longer supported to work on your machine. Though the backup client may appear to run, results of such backups are unpredictable, and it is important to upgrade. There is no need to uninstall the old version of the backup software before installing the new one.
  • Changing operating system by moving to a new machine - if you are moving between similar operating systems, for example replacing a machine running Windows 7 with one running Windows 10, then you may keep your existing HFS account name. But if you are changing platform - moving between Windows, Mac and Linux - then please register a new HFS account. This is because the backup software does not support cross-platform restores, so you cannot swap between Windows, Mac and Linux. If you do, you may corrupt your account and so render your data inaccessible.
  • Moving your computer's location - DNS/IP address changes are not important, that is to say, moving your machine and backing up from a different location will not cause any problems; nor will it cause data to be resent.

5. Keep data sets to a manageable size

The HFS backup client works on each data partition/drive as a whole. It composes a list of what is on your machine, compares that with what is stored on the HFS server already, and backs up the difference. If, therefore, you have many millions of files in one partition, the backup client on your local machine can become very slow as it tries to process the whole list at once. Before you first back up, please first of all consider the arrangement of your data and split it into partitions - ideally of no more than 1TB and a few million files in each.

6. Cease backing up from drives whose data is needed for restores

If data is lost from your machine and you then run a further backup, then the copies of those files on the HFS are scheduled for deletion, and only kept for up to 90 days. So if you lose data from (for example) a Windows drive C: and then back up C:, the HFS copies of your data are at risk. We therefore recommend that as soon as you discover you have lost data from an existing machine, you stop your backup scheduler. For how to do this, please see our instructions for Windows, Mac, Linux. and Solaris. Alternatively, please email us at and ask for your data set to be renamed, so that you do not accidentally back up over it.

7. Register one account per operating system

You can register as many HFS accounts as you need in order to back up your data. For most people this will mean one HFS account name per physical machine, though in the case of a multi-boot machine an HFS account name is needed for each operating system that you wish to back up. So, for example, if you manage a lab of machines all running just Windows, then you may register each one; or if you have a dual-boot machine running Windows and Linux then you should register for two TSM accounts, if you wish to back up both operating systems. However:

  • Please do not attach more than one machine to an HFS account. This can happen accidentally if you install the backup software on a machine and then clone that machine and give it a new identity. In such situations, especially on Mac and Linux, one machine can overwrite the other's data on the HFS. This is waste of resources and furthermore puts your backups in danger.
  • Please do not register the same machine twice. This is a waste of HFS software licences and, if you back up the same data to two accounts, it causes data duplication at the HFS end.
  • If you wish to transfer an HFS account name from one machine to another, please email us at Do not deregister the account name and then re-register it: we do not delete accounts immediately, instead rolling up our deletions in batches and performing them on a large group of deregistered accounts at once. If you re-register the same account name, our deletions script will assume that the two identically-named accounts are unwanted, and will mark them both for deletion. You therefore cannot re-register a recently-deregistered account name for several days, and sometimes for up to two weeks, unless you contact us and ask us to delete the old account manually.

8. Let us know if you stop using the HFS

In order to manage our system efficiently, the HFS Team will remove any backup account, including its data, that has not backed up for 90 days or more; and, similarly, any individual partitions which are in an active account but which have not been backed up for 90 days or more will be deleted. Before doing so, we attempt to inform the registered contact with up to three warning mails. This process is described in our page on deleting old backups.

8.1. If you go away temporarily

We can keep your data for you while you are away, if you are leaving Oxford temporarily and cannot back up regularly - for example because you are on extended leave away and your machine is in Oxford. Contact to ask us to retain your backups, letting us know when you will be away till. Please note that we can keep data from dormant accounts only for a reasonable period of time.

8.2. If you leave Oxford University

If you have finished with your HFS backup account, please uninstall the HFS backup software and deregister your HFS account. This saves resources at the HFS end, as otherwise we retain unused accounts for up to 90 days before deletion.

Written by IT Services. Latest revision 27 November 2017