Hi Eric, Yes, I understand what you are saying about the interaction between ordered data mode and DA in ext4. It's the combination of the 2 options that makes the difference. Merely having a switch to turn off DA on XFS would not get me what I need for my data volumes. But thank you for making that explicit. I intentionally disable DA on my ext4 data volumes specifically to get ext3-like behavior which results in a night and day difference in resiliency during... difficult times... for many of my customers, in my repeated experiences. I could just use ext3. But why give up extents, multiblock allocation, CRC protection of the journal, etc? (BTW, that's my vote *not* to remove the nodelalloc option of ext4 as I noticed you and Ted discussing last April. ;-) So on a set of Cobol C/ISAM files which never get fsync'd or fdatasync'd, (because that concept does not exist in Cobol) would you expect there to be any difference in the resiliency of ext4 and xfs with both filesystems at completely default settings? Or would it be about the same. I'm *very* interested in this topic, as I'd like the best speed and more filesystem options, but need the resiliency even more for many of my servers. Do I have an option with XFS to improve behavior on/after an unclean shutdown? If so, I'd sincerely like to know. XFS is an excellent filesystem. Indispensable for certain use-cases. If you need > 16TB files, there's nothing like it. (And I'm sure there are other good use-cases.) Similarly, DA is a valuable filesystem feature. And I'm very glad that both XFS & Ext4 have it available to me. But as with any filesystem or fs feature, there are always trade-offs, risks and benefits, etc. And those differences have turned out to be crucially important to me and to quite a number of my customers. -Steve -- To unsubscribe from this list: send the line "unsubscribe linux-raid" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
