hpc / hpc/mpifileutils

dbz2: add sparse file support

Open
#300 0 comments 0 reactions 0 assignees View on GitHub

Nobody has claimed this yet.

Dominant language
C
Stars
200
Forks
85
Avg merge
3d 21h
Merged PRs (30d)
2

Description

When compressing a sparse file with dbz2, it would help to only read the valid file extents.

When decompressing a sparse file, it would help to only write the non-zero blocks.

When storing the file in compressed form, assuming a good compression algorithm the compressed file itself is likely to be non-sparse, so we probably don't need to worry about 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 at the dbz2 compression and decompression entry points, then trace how file extents and blocks are read and written. Determine how to read only valid sparse-file extents during compression and write only non-zero blocks during decompression. Done means sparse inputs avoid unnecessary I/O while the resulting files retain their expected contents and layout.

Written by the indexing model from the issue text.

Assessment

Tech stack
c
Domain
cli, tooling
Issue type
Feature
Difficulty
4/5
Estimated time
3-5 days
Activity status
Stale
Clarity
Mostly clear
Newbie friendliness
42/100

Get new issues in your inbox

A short digest of beginner-friendly GitHub issues.