SSD and non-SSD Suitability
I've got a somewhat broad question on the suitability of nilfs for various workloads and different backing storage devices. From what I understand from the documentation available, the idea is to always write sequentially, and thus avoid slow random writes on old/naive SSDs. Hence I have a few questions. 1) Modern SSDs (e.g. Intel) do this logical/physical mapping internally, so that the writes happen sequentially anyway. Does nilfs demonstrably provide additional benefits on such modern SSDs with sensible firmware? 2) Mechanical disks suffer from slow random writes (or any random operation for that matter), too. Do the benefits of nilfs show in random write performance on mechanical disks? 3) How does this affect real-world read performance if nilfs is used on a mechanical disk? How much additional file fragmentation in absolute terms does nilfs cause? 4) As the data gets expired, and snapshots get deleted, this will inevitably lead to fragmentation, which will de-linearize writes as they have to go into whatever holes are available in the data. How does this affect nilfs write performance? 5) How does the specific writing amount measure against other file systems (I'm specifically interested in comparisons vs. ext2). What I mean by specific writing amount is for writing, say, 100,000 random sized files, how many write operations and MBs (or sectors) of writes are required for the exact same operation being performed on nilfs and ext2 (e.g. as measured by vmstat -d). Many thanks. Gordan -- To unsubscribe from this list: send the line unsubscribe linux-nilfs in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Re: gentoo amd64 based bootable cd with latest kernel and nilfs2 utils
On Wed, 26 May 2010 08:05:40 +0900, Jiro SEKIBA wrote: Hi, At Tue, 25 May 2010 03:30:32 +0900 (JST), Ryusuke Konishi wrote: Hi, On Mon, 24 May 2010 17:11:51 +0200, David Arendt wrote: Hi, In order to facilate problem solving for the case my system using nilfs2 as root filesystem is not booting correctly, I created a gentoo amd64 based boot cd using latest kernel and nilfs2 utilities. If you think it could be usefull for other people too, I could either create an own webpage to host the iso image or you could add it to the main nilfs2 site. What do you think ? Yes, I think this kind of rescue drives are helpful transiently. Quite similaly, I have a usb pendrive with nilfs-utils and nilfs kmod to maintain my nilfs root debian system just in case. We can afford to put the iso image that you kindly collected up for people on nilfs.org, but it seems better that you have your own site because organizing information how to use that, looks more important to me. Can't say as I do. Anyone have any ideas ? It would be convenient to just have a link to David's page from nilfs.org. And maybe a link to Paul's page too :), if it's not cumbersome. I did it. Thanks! Ryusuke Konishi -- To unsubscribe from this list: send the line unsubscribe linux-nilfs in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
