news_iconCFHT Observer Tape Backup Facilities

This is an overview of what tape drive facilities are available for observers at CFHT. It is imperative that data be stored to tape at the summit, rather than in Waimea. This is because there may not be enough disk space at the summit to save your data beyond the day your run ends. While CFHT will make every effort to save your data on the summit disk if there is some "emergency", sufficient disk space must be available for the next observer. Also, CFHT does not permit standard remote access into CFHT, i.e., rlogin, rsh, telnet, and ftp (other than anonymous) are not accepted. Thus, you can't depend on retrieving data once you have left CFHT even if it was possible to save your data on disk. Note that there are no CFHT restrictions from CFHT out to the Internet.

The observer is responsible for backing up data to tape so please don't ask CFHT staff to perform tape backups for you. Of course, there are circumstances when CFHT staff will need to help you. If some disaster occurs at the summit such that you cannot back up your data at the summit, you may travel to the Waimea headquarters to perform backups. If your data is still located on the summit data disk, then you may use one of the Waimea tape drives to finish the backup process. If your data is not available on the summit data disk, then you will need to contact your support astronomer for help. In this case the data must be extracted from the CFHT archive tapes. It is difficult to predict how long this process will take.

For general information about tapes, tape devices and using tapes see the tape information page in the CFHT archive manual.

DLT WARNING: Each time a DLT tape is inserted into a DLT drive the tape must be inspected. Aside from physical damage to the tape, the primary thing to check is that the tape leader is visible. To check this open the tape cartridge door at the back of the tape. Inside the door you will see the tape and cartridge leader loop. If the loop is torn, pulled in, or not sticking up about an eighth of an inch when viewed from the edge, DO NOT use the tape. Using a tape which has a faulty leader will render the drive inoperable.

Tape Drive Facilities at the Summit:

There are tape drives in the observing room that are for use by observers:

DAT DDS3 - onohi:/dev/dat
Exabyte - onohi:/dev/exb
DLT 7000 - onohi:/dev/dlt

They are physically attatched to machine onohi and can be used remotely by using gnu tar and remote device names from any other computer at the summit. Eg:

[kanoa@mahina:/data/mahina/] gtar -cvf onohi:/dev/dlt my_stuff/

Or by logging into onohi and using the local device name:

[kanoa@onohi:/data/mahina/] gtar -cvf /dev/dlt my_stuff/

CFHT maintains a supply of the following tape media at the summit:

  • Exabyte - 5 gb capacity
  • DAT - 2 gb capacity
  • DAT DDS3 - 12 gb capacity
  • DLT IV - 35 gb capacity
Please inform CFHT beforehand if you anticipate using a large number of tapes so that we have an adequate number on hand. The observing assistant will fill out a form to reflect the tapes you use, and tape charges will be added to your bill.

Tape Drive Facilities at the Waimea Headquarters:

There are a number of tapes drives available in Waimea. These include DLT7000, standard Exabyte, mammoth Exabyte and DAT drives. A complete list of tape facilities at CFHT is available here. Please ask your support astronomer for help if you need to use tape drives in Waimea.

This page is maintained by: Kanoa