From mboxrd@z Thu Jan 1 00:00:00 1970 From: Alex Zhuravlev Date: Tue, 19 Feb 2008 15:13:08 +0300 Subject: [Lustre-devel] storing SOM epoch in EA In-Reply-To: <47BAC53A.2030106@sun.com> References: <47BAA607.1000600@sun.com> <47BAAF3F.6030301@sun.com> <200802191359.47379.vitaly@sun.com> <47BAB962.8010901@sun.com> <47BABB01.8060402@sun.com> <47BAC53A.2030106@sun.com> Message-ID: <47BAC7D4.3010007@sun.com> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: lustre-devel@lists.lustre.org btw, are you proposing to store LOV in global IAM? thanks, Alex Yuriy Umanets wrote: > Seriously, IMHO what is bad about EAs: > > 1. You need to control their size, you need to bother; > 2. Large-fast inodes make create/lookup slow. You need to load this > thing to memory after all. I think this is complement to additional > seeks caused by IAM; > 3. Storing epoch in EA makes you use this chain to access epoch: > fid->inode->epoch (in EA), IAM makes it shorter: fid->epoch (in IAM); > 4. Large inodes consume more RAM; > 5. There others... but they are less related to technical > downsides/advantages so I will omit them. > > Thanks. >