Gentoo Archives: gentoo-user

From: Rich Freeman <rich0@g.o>
To: gentoo-user@l.g.o
Subject: Re: [gentoo-user] SDD strategies...
Date: Tue, 17 Mar 2020 14:15:07
Message-Id: CAGfcS_mBNjXjzyD5ynp03VswtQKExVcLfyipvUk8xXaHztzV3A@mail.gmail.com
In Reply to: [gentoo-user] SDD strategies... by tuxic@posteo.de
1 On Tue, Mar 17, 2020 at 1:59 AM <tuxic@××××××.de> wrote:
2 >
3 > The HD will contain the whole system including the complete root
4 > filesustem. Updateing, installing via Gentoo tools will run using
5 > the HD. If that process has ended, I will rsync the HD based root
6 > fileystem to the SSD.
7 > ...
8
9 I'll go ahead and write one consolidated reply to a couple of points
10 raised in these two threads to save everybody emails.
11
12 First, I'll echo what was said about this being probably an
13 overly-complex solution to the problem. I think you'll spend more
14 time dealing with this than with any SSD failure issues.
15
16 Next, in general you tend to get what you pay for. With SSDs if
17 you're getting that bargain 512GB drive for $15 when all the
18 comparable drives are $70, and it was made by some company you've
19 never heard of, chances are that you're missing something. I'm not
20 saying you need to go buy that 150% more expensive "signature edition"
21 drive or whatever, though it might very well have some feature that
22 justifies its price. Just be wary if things that look too good to be
23 true. If you buy a reputable brand that is marketed for your intended
24 use chances are you're getting something decent, even if you're paying
25 10% more. If you really know what you're doing you can certainly use
26 research to save money by critically evaluating your options.
27
28 Finally, ALL DRIVES FAIL. It doesn't matter what the underlying
29 storage technology is. I've seen hard drives fail in less than a
30 year, with the warranty replacement drive failing less than a year
31 after that. I think next warranty replacement (still in the original
32 warranty period) lasted 5+ years of near-continuous use. The typical
33 failure modes of hard drives and solid state storage are different,
34 but they all fail. You can't perfectly predict WHEN they will fail
35 either. Most drives have SMART and sometimes it can detect failure
36 conditions before failure, but not always.
37
38 What will you do when your brand new drive fails 3 weeks after you buy
39 it? If you don't have an answer that doesn't involve you losing stuff
40 you don't want to lose, or having downtime you don't want to have,
41 then you need to re-evaluate your approach. Backups and RAID are the
42 obvious solutions - with backup generally being the more reliable
43 solution to data loss, and RAID being the more reliable solution to
44 downtime, but with them both having some overlap.
45
46 Here is what I've done:
47 1. Preferred solution to SSD failure and associated downtime is
48 RAID+backups. The most important stuff is backed up to the cloud,
49 encrypted. With SSDs I usually do a full backup to hard drives since
50 that is fairly inexpensive given their relative capacities. I'm using
51 ZFS mirroring as my RAID-like solution right now, and I use
52 ZFS-send/receive to do hourly backups that are very low overhead.
53
54 2. If I'm too cheap to use RAID on a host then I just do the hourly
55 ZFS remote snapshots - that is a good solution on hosts where downtime
56 doesn't matter, because I can just get a new drive and restore the
57 snapshot and I'm back in business after a day or two, accepting a one
58 hour recovery point objective.
59
60 You can of course use rsync as well.
61
62 For rsync-based backups I recommend rsnapshot, in portage.
63 For zfs remote snapshots I have switched to zfs_autobackup:
64 https://github.com/psy0rz/zfs_autobackup/blob/master/README.md
65
66
67 --
68 Rich

Replies

Subject Author
Re: [gentoo-user] SDD strategies... james <garftd@×××××××.net>