There are a couple things to check when using Windows PreRollPost to write or read from LTO tapes to make sure you're getting the best performance.


Virus Protection


The first, check is to make sure you don't have a virus protection application enabled while reading or writing to tape. You also need to add your tape drive to the list of exclusions in Windows Defender (see separate FAQ for instructions on how to configure Windows Defender).


Extended Attributes


Because LTO retrieval functions depend upon knowing where the requested file is on the tape, PreRoll Post attempts to access the tape's extended attributes to acquire the block (location) information from the index. To do that requires installation of the 'LTFS get extended attributes' routines on your PC. A 'ltfsgetea' file is generally included with LTFS driver installers, however some recent IBM provided drivers are known to have overlooked this important file. (find those instructions here).


Write Sequence


Since LTO tapes are a linear media it does matter what sequence files are added to it and referenced later. Generally you have the option to write files by File size or Alphabetically. If a tape was created using one of these settings and you're attempting to retrieve files in the other mode it can slow down the restore process, especially if you're attempting to retrieve multiple files at one time. In Advanced Preferences switch the setting to test if switching modes helps speed up file access.


Reports


The PreRoll Post application has the option to create reports of both archive sessions to the tape as well as retrievals from the tape. To speed up reports while writing to tape you can choose a Text type report instead of PDF. PDF reports are slower to process because they require accessing the source files again after copying is completed to gather metadata information and thumbs for video files. Text type reports don't require this additional step.

You can also turn off reports altogether in Report Preferences and just create them later when needed from the database. Likewise when restoring files, it's a good idea to disable reports unless they're really needed.


Verification Settings


All LTO tape drives have built-in dual write/read heads and automatically check each byte written to the tape by immediately reading it back. This function allows the drive to detect bad sections of tape media and rewrite files automatically should any mismatch be found. The CRC hash method used also allows a high degree of confidence that the data is intact so additional checksum analyses are not necessary. PreRoll Post does offer checksum verification should your workflow or clients require the values, but please realize using an MD5 or XXHash setting requires a full read back of the tape, essentially doubling the creation time needed. Also, any read back from tape bears the potential slowness imposed by virus protection scans such as those performed by Windows Defender. (refer to Virus Protection information above). For more information on checksums please check out our three part blog.