Gentoo Archives: gentoo-user

From: Andrew Savchenko <bircoph@g.o>
To: gentoo-user@l.g.o
Subject: [gentoo-user] Filesystem choice for NVMe SSD
Date: Sun, 24 Jan 2016 00:44:52
1 Hi,
3 I plan to use NVMe SSD on my desktop and I'm quite puzzled with
4 the filesystem choice :/ So community input on this matter will be
5 very valuable.
7 Typical anticipated workload: root filesystem, a lot of small and
8 middle sized files (e.g. source code), tons of compiling, ccache,
9 testing and similar dev activity. Large and media files will be
10 stored on another dedicated host.
12 What I want (just random order, so last is not the least):
14 1. Reasonable reliability. I'll have regular backups on an external
15 media, but I don't want to have my root corrupted often.
17 2. Minimized media wear-out. Filesystem should be friendly to NVMe:
18 for 512GB size it have only 400 TBW warranty :/
20 3. Performance. This is natural to strive to get full speed and
21 minimal latency from such a yummy storage.
23 For now I consider the following solutions:
24 a) EXT4
25 b) XFS
26 c) F2FS
27 d) BTRFS
29 a) EXT4 is a good extremely robust solution. Reliability is out of
30 the questioning: on my old box with bad memory banks it kept my data
31 safe for years, almost all losses were recoverable. And it has some
32 SSD-oriented features like discard support, also stripe and stride
33 with can be aligned to erase block size to optimize erase
34 operations and reduce wear-out.
36 b) In some tests XFS is better than EXT4 ([1] slides 16-18; [2]).
37 Though I had data loss on XFS on unclear shutdown events in the
38 past. This was about 5 years ago, so XFS robustness should have
39 improved, of course, but I still remember the pain :/
41 c) F2FS looks very interesting, it has really good flash-oriented
42 design [3]. Also it seems to beat EXT4 on PCIe SSD ([3] chapter
43 3.2.2, pages 9-10) and everything other on compile test ([2] page 5)
44 which should be close to the type of workload I'm interested in
45 (though all tests in [2] have extra raid layer). The only thing
46 that bothers me is some data loss reports for F2FS found on the
47 net, though all I found is dated back 2012-2014 and F2FS have fsck
48 tool now, thus it should be more reliable these days.
50 d) I'm not sure about BTRFS, since it is very sophisticated and I'm
51 not interested in its advanced features such as snapshots,
52 checksums, subvolumes and so on. In some tests [2] it tends to
53 achive better performance than ext4, but due to its sophisticated
54 nature it is bound to add more code paths and latency than other
55 solutions.
58 So, for now I tend to use F2FS for / and test other filesystems for
59 some load (e.g. compile chromium or libreoffice there). It will be
60 hard to do good tests, though, because the drive has built-in DDR3
61 512 MB memory cache which will affect results and I have now idea
62 how to flash it other than reboot the host.
64 But all these considerations are based on theory and tests found on
65 the net. I have little practical experience with SSDs other than USB
66 sticks and SD cards, so any feedback and practical experience share
67 is appreciated.
69 P.S. Is aligning to erase block size really important for NVMe? I
70 can't find erase block size for this drive (Samsung MZ-VKV512)
71 neither in official docs nor on the net...
73 [1]
74 [2]
75 [3]
77 Best regards,
78 Andrew Savchenko


Subject Author
Re: [gentoo-user] Filesystem choice for NVMe SSD Rich Freeman <rich0@g.o>
[gentoo-user] Re: Filesystem choice for NVMe SSD James <wireless@×××××××××××.com>