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Recovering lost data » History » Version 3

Tom Clegg, 04/26/2019 07:58 PM

1 1 Tom Clegg
h1. Untrashing lost blocks
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In some cases it is possible to recover data blocks that have been trashed by keep-balance (due to a bug or an install/config error).
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If you suspect blocks have been trashed erroneously, you should immediately:
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# On all keepstore servers: set EmptyTrashInterval to a long time like 2400h
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# On all keepstore servers: restart keepstore
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# Stop the keep-balance service
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When you think you have corrected the underlying problem, you should:
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# Set LostBlocksFile to a suitable value (perhaps "/tmp/keep-balance-lost-blocks.txt") in your keep-balance config
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# Start keep-balance
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After keep-balance completes its first sweep, inspect /tmp/keep-balance-lost-blocks.txt. If it's not empty, you can request all keepstores to untrash any blocks that are still recoverable with a script like this:
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<pre><code class="bash">
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#!/bin/bash
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set -e
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# see Client.AuthToken in /etc/arvados/keep-balance/keep-balance.yml
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token=xxxxxxx-your-system-auth-token-xxxxxxx
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# all keep server hostnames
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hosts=(keep0 keep1 keep2 keep3 keep4 keep5)
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26 3 Tom Clegg
while read hash pdhs; do
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    echo "${hash}"
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    for h in ${hosts[@]}; do
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        if curl -fgs -H "Authorization: Bearer $token" -X PUT "http://${h}:25107/untrash/$hash"; then
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            echo "${hash} ok ${host}"
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        fi
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    done
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done < /tmp/keep-balance-lost-blocks.txt
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</code></pre>