https://tracker.ceph.com/https://tracker.ceph.com/favicon.ico2018-05-14T17:06:31ZCeph CephFS - Bug #24074: Read ahead in fuse client is broken with large buffer sizehttps://tracker.ceph.com/issues/24074?journal_id=1131532018-05-14T17:06:31ZGreg Farnumgfarnum@redhat.com
<ul><li><strong>Project</strong> changed from <i>Ceph</i> to <i>CephFS</i></li></ul> CephFS - Bug #24074: Read ahead in fuse client is broken with large buffer sizehttps://tracker.ceph.com/issues/24074?journal_id=1131882018-05-14T22:10:30ZPatrick Donnellypdonnell@redhat.com
<ul><li><strong>Status</strong> changed from <i>New</i> to <i>Need More Info</i></li><li><strong>Target version</strong> set to <i>v14.0.0</i></li><li><strong>Source</strong> set to <i>Community (user)</i></li><li><strong>Backport</strong> set to <i>mimic,luminous</i></li><li><strong>Component(FS)</strong> <i>Client</i> added</li><li><strong>Labels (FS)</strong> <i>task(intern)</i> added</li></ul><p>Chuan Qiu wrote:</p>
<blockquote>
<p>If the read is larger than 128K(e.g. 4M as our object size), fuse client will receive read requests as multiple ll_read of 128K(due to 32 page kernel limit).</p>
<p>Fuse client is actually sending multiple requests to read 128K, instead of a request of 4M. Read ahead is also not happening.</p>
<p>Could we either increase the max read size for ll_read, or fix the readahead to make it actually send the request with size 4M.</p>
<p>Here is the debug_ms history with a single OSD.<br />[...]</p>
</blockquote>
<p>Have you tried changing the file layouts?</p>
<p><a class="external" href="http://docs.ceph.com/docs/master/cephfs/file-layouts/">http://docs.ceph.com/docs/master/cephfs/file-layouts/</a><br /><a class="external" href="http://docs.ceph.com/docs/master/dev/file-striping/">http://docs.ceph.com/docs/master/dev/file-striping/</a></p>
<p>Please let us know what configuration you have for your client and a snippet of a `debug client = 20` log to help diagnose.</p> CephFS - Bug #24074: Read ahead in fuse client is broken with large buffer sizehttps://tracker.ceph.com/issues/24074?journal_id=1131962018-05-15T03:53:23ZZheng Yanukernel@gmail.com
<ul></ul><p>try passing '--client_readahead_max_bytes=4194304' option to ceph-fuse</p> CephFS - Bug #24074: Read ahead in fuse client is broken with large buffer sizehttps://tracker.ceph.com/issues/24074?journal_id=1309792019-03-07T23:21:37ZPatrick Donnellypdonnell@redhat.com
<ul><li><strong>Target version</strong> changed from <i>v14.0.0</i> to <i>v15.0.0</i></li></ul> CephFS - Bug #24074: Read ahead in fuse client is broken with large buffer sizehttps://tracker.ceph.com/issues/24074?journal_id=1561222020-01-17T22:53:46ZPatrick Donnellypdonnell@redhat.com
<ul><li><strong>Target version</strong> deleted (<del><i>v15.0.0</i></del>)</li></ul>