al3xu5 via Dng said on Sun, 18 Jun 2023 13:24:14 +0200
>Hi all
>
>I apologize if I'm OT... but I would like advice from you.
>
>My current system derives from a migration from Debian to Devuan
>carried out since the "origins", even before Jessie, then updated over
>the years to Chimaera.
>
>The system is installed on a WD Velociraptor 250GB 10000rpm,
>with Power_On_Hours of over 10000 Hours. Other info: LXDE Desktop, RAM
>32GB.
>
>I am considering replacing the system disk with an SSD SATA SAMSUNG
>870EVO 500GB (1.5 Million Hours MTBF) on which to proceed with a fresh
>installation of Daedalus.
>
>There is also a second mechanical disk (MDM RAID: 2x 1TB mirrored)
>whose partitions are mounted on /media.
>
>I also have an external backup of the WHOLE system ;-)
>
>The basic idea is to use the SSD disk for the system, moving the
>partitions (or directories) on which the most writes take place to the
>mechanical disk, also by accepting a compromise between speed and
>duration of the SSD disk.
The preceding paragraph is what I've been doing for years. The root
partition on an NVMe SSD, and all my changing data on spinning rust.
>
>For this I would like to know your opinions and suggestions.
>
>Currently:
>
>$ lsblk
>NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT
>sda 8:0 0 232,9G 0 disk
>├─sda1 8:1 0 46,6G 0 part /
>├─sda2 8:2 0 93,1G 0 part /home
/home belongs on your sdc drive. There might be arguments for putting
either/or /tmp, /var and/or [swap] on spinning rust, as they get
written to A LOT. Most computers have /tmp as a tmpfs that exists only
in RAM and isn't persistent.
>├─sda3 8:3 0 1K 0 part
>├─sda5 8:5 0 55,9G 0 part /tmp
>├─sda6 8:6 0 18,6G 0 part /var
>└─sda7 8:7 0 14,9G 0 part [SWAP]
>...
>sdc 8:32 0 932G 0 disk
>├─sdc1 8:33 0 233G 0 part
>│ └─md1 9:1 0 233G 0 raid1 /media/DATA
>├─sdc2 8:34 0 275G 0 part
>│ └─md2 9:2 0 275G 0 raid1 /media/MISC
>├─sdc3 8:35 0 275G 0 part
>│ └─md3 9:3 0 275G 0 raid1 /media/SOFTWARE
>└─sdc4 8:36 0 138G 0 part
> └─md4 9:4 0 138G 0 raid1 /media/VM
>
>My hypothesis is:
>
>- system disk (SSD 500GB):
>TYPE SIZE MOUNTPOINT
>part 50G /
>part 50G /home
>part 200G /media/VM <-- moved from sdc disk
> 200G [unused]
>- other mechanical disk
>TYPE SIZE MOUNTPOINT
>...
>part 60G /tmp
>part 20G /var
>part 16G [SWAP]
Why is /tmp so big?
>...
>- using symbolic links: "move" /home/desktop and
>/home/downloads to /media/DATA (on the sdc mirrored disk)
Do you mean bind mounts?
>
>
>The first big question is: is it still appropriate, with current SSD
>discs, try to reduce writings?
Yes. Not nearly as important as in the past, but still a good idea for
letting SSDs live a long and happy life. Also, SSDs shouldn't, in my
opinion, get over 50% full.
>
>And then: which mechanical disk should be used for /tmp, /var, swap
>etc...? Better reuse the "old" non-raid system disk (WD 10000rpm), or
>the actual mirrored sdc disk (see above)?
You don't say how big the mirrored disk is, but if it's a dinky 1TB
like your 10000rpm I'd advise buying a new disk that holds at least
8TB, and 12, 14, or 16TB would be any better.
>Other doubts are:
>- Is it worth bringing with symbolic links /home/desktop and
> /home/downloads on the mechanical mirrored disk (sdc)?
I'd put the entire /home partition on the spinning rust.
>- About /var: could I limit myself to "move" using symbolic links only
> /var/log, /var/mail, /var/spool, /var/tmp?
By the time you do that, why not just put all of /var on the spinning
rust?
>- Does this complexity risk leading to an unstable or fragile system?
It sure hasn't for me. But I use bind mounts, not symlinks.
>- Is this complexity justified compared to the longer duration of the
>SSD disc?
I don't see it as that complex, and if you use your disks hard, I'd
call it justified.
>- What else I'm not considering and/or evaluating?
Friends don't let friends use Seagate drives. I recommend Western
Digital.
SteveT
Steve Litt
Autumn 2022 featured book: Thriving in Tough Times
http://www.troubleshooters.com/bookstore/thrive.htm