LinearTapeFileSystem / LinearTapeFileSystem/ltfs

Read performance - ok / optimal

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enhancement Hacktoberfest help wanted
Dominant language
C
Stars
352
Forks
110
Avg merge
2h 50m
Merged PRs (30d)
2

Description

I see there's another issue about read performance but that seems to be about a specific bug / environment so I'll create a new one.

Using M8 media in an HPE LTO8 autoloader, what is considered the best possible read performance currently? I'm seeing around 275-280 MB/s writes, which is very close to my raw tape speed, and 210 MB/s reads (+/- 10 MB/s). 210 MB/s is fine, but as always faster would be better. I'm using the latest master in Debian 10 on a xeon 2155 , 256 GB RAM and enterprise nvme drives. The files on the tape are 50-500 MB and I've tried using ltfs_ordered_copy and my own file copier with about the same result.

Is this the expected speed, or is there something I can do to improve it?

Contributor guide

Open the contributing guide

First steps

  1. Read the whole issue, then the project's contributing guide.
  2. Comment on the issue to say you are picking it up — it saves two people doing the same work.
  3. Fork the repository and make your change on a branch.
  4. Open a pull request that references the issue number.

Research direction

Start by reproducing the reported read workload with ltfs_ordered_copy on the stated HPE LTO8/M8 setup and compare it with the custom file copier. Review the latest master behavior and determine whether the reported read speed is expected or whether a reproducible improvement is identified.

Written by the indexing model from the issue text.

Assessment

Tech stack
c, debian
Domain
performance
Issue type
Bug
Difficulty
5/5
Estimated time
Over a week
Activity status
Stale
Clarity
Needs clarification
Newbie friendliness
18/100

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