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cache_writeback(8) System Manager's Manual

📛 NAME

cache_writeback - writeback dirty blocks to the origin device.

🚀 Quick Reference

Use Case	Command	Description
💾 Writeback dirty blocks	cache_writeback --metadata-device {device} --origin-device {device} --fast-device {device}	Write back dirty cached data to the origin device
❌ List failed blocks	cache_writeback --metadata-device {device} --origin-device {device} --fast-device {device} --list-failed-blocks	List any blocks that failed the writeback process

📝 SYNOPSIS

cache_writeback [options] --metadata-device {device|file} --origin-device {device|file} --fast-device {device|file}

📖 DESCRIPTION

cache_writeback is an offline tool that writes back dirty data to the data device (origin). Intended for use in recovery scenarios when the SSD is giving IO errors.

⚠️ This tool cannot be run on a live cache.

⚙️ OPTIONS

🆘 -h, --help

Print help and exit.

ℹ️ -V, --version

Print version information and exit.

💾 --metadata-device {device|file}

Location of cache metadata.

🐌 --origin-device {device|file}

Slow device being cached.

⚡ --fast-device {device|file}

Fast device containing the data that needs to be written back.

🚫 --no-metadata-update

Do not update the metadata to clear the dirty flags.

You may want to use this flag if you're decommissioning the cache.

📦 --buffer-size-meg {size}

Specify the size for the metadata cache.

Defaults to 16 Gig, a larger size may improve performance.

❌ --list-failed-blocks

List any blocks that failed the writeback process.

📚 SEE ALSO

cache_dump(8), cache_check(8), cache_repair(8), cache_restore(8)

✍️ AUTHOR

Joe Thornber <ejt AT redhat.com>

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System Manager's Manual Device Mapper Tools cache_writeback(8)

📛 NAME 🚀 Quick Reference 📝 SYNOPSIS 📖 DESCRIPTION ⚙️ OPTIONS 📚 SEE ALSO ✍️ AUTHOR