From mboxrd@z Thu Jan 1 00:00:00 1970 From: Alexander Tsvetkov Subject: bigalloc cluster size Date: Tue, 21 Apr 2015 16:31:20 +0300 Message-ID: <55365128.206@oracle.com> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit To: linux-ext4@vger.kernel.org Return-path: Received: from userp1040.oracle.com ([156.151.31.81]:27292 "EHLO userp1040.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753261AbbDUN2R (ORCPT ); Tue, 21 Apr 2015 09:28:17 -0400 Received: from userv0022.oracle.com (userv0022.oracle.com [156.151.31.74]) by userp1040.oracle.com (Sentrion-MTA-4.3.2/Sentrion-MTA-4.3.2) with ESMTP id t3LDSGpC019565 (version=TLSv1 cipher=DHE-RSA-AES256-SHA bits=256 verify=OK) for ; Tue, 21 Apr 2015 13:28:16 GMT Received: from userv0121.oracle.com (userv0121.oracle.com [156.151.31.72]) by userv0022.oracle.com (8.13.8/8.13.8) with ESMTP id t3LDSGnH031395 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=FAIL) for ; Tue, 21 Apr 2015 13:28:16 GMT Received: from abhmp0019.oracle.com (abhmp0019.oracle.com [141.146.116.25]) by userv0121.oracle.com (8.13.8/8.13.8) with ESMTP id t3LDSFeM003551 for ; Tue, 21 Apr 2015 13:28:16 GMT Sender: linux-ext4-owner@vger.kernel.org List-ID: Hello, I've noted that valid cluster size is not limited by 256M according to "mke2fs" manual: "-C cluster-size Specify the size of cluster in bytes for filesystems using the bigalloc feature. Valid cluster-size values are from 2048 to 256M bytes per cluster." but actually it's limited by 512M: "[root@fedora ~]# mkfs.ext4 -O bigalloc -C 512m /dev/sdb mke2fs 1.43-WIP (29-Mar-2015) /dev/sdb contains a ext4 file system created on Tue Apr 21 15:30:27 2015 Proceed anyway? (y,n) yes Warning: the bigalloc feature is still under development See https://ext4.wiki.kernel.org/index.php/Bigalloc for more information Creating filesystem with 2097152 4k blocks and 16 inodes Allocating group tables: done Writing inode tables: done Creating journal (32768 blocks): done Writing superblocks and filesystem accounting information: done [root@fedora ~]# mkfs.ext4 -O bigalloc -C 1024m /dev/sdb mkfs.ext4: invalid cluster size - 1024m" (running on vbox Fedora x86_64, latest e2fsprogs, kernel 4.0.0-rc5) Is it documentation issue? Thanks, Alexander Tsvetkov