From mboxrd@z Thu Jan 1 00:00:00 1970 From: Mark Kirkwood Subject: Re: ceph-disk vs keyvaluestore Date: Thu, 02 Oct 2014 12:46:44 +1300 Message-ID: <542C9264.9090300@catalyst.net.nz> References: Mime-Version: 1.0 Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit Return-path: Received: from bertrand.catalyst.net.nz ([202.78.240.40]:59582 "EHLO mail.catalyst.net.nz" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751806AbaJAXqt (ORCPT ); Wed, 1 Oct 2014 19:46:49 -0400 In-Reply-To: Sender: ceph-devel-owner@vger.kernel.org List-ID: To: Sage Weil , Haomai Wang Cc: "ceph-devel@vger.kernel.org" On 30/09/14 17:05, Sage Weil wrote: > On Tue, 30 Sep 2014, Haomai Wang wrote: >> Hi sage, >> >> What do you think use existing ObjectStore::peek_journal_fsid >> interface to detect whether journal needed. >> >> KeyValueStore and MemStore could set passing argument "fsid" to zero >> to indicate no journal. > > I'm not sure it's a good fit... it's called on an existing store and tells > you something about it. I would probably expect a zeroed fsid to mean > that the specified journal is empty or does not exist, not that it doesn't > need to exist. > > What we need, on the other hand, is something that just tells us whether > we should create a journal... > > And perhaps the "type" (probably not the right word) of journal: - filestore: device or filesystem - rocksdb: filesystem (wal directory) - leveldb: none (I think) FWIW, it looks like the log files for leveldb *could* benefit from being placed somewhere else (e.g on faster storage). Is it worthwhile suggesting to the leveldb devs? Cheers Mark