Re: [gentoo-user] Seagate hard drives with dual actuators.

[Rich Freeman <rich0@gentoo.org>]

On Thu, Nov 14, 2024 at 6:10 PM Dale <rdalek1967@gmail.com> wrote:
>
> The biggest downside to the large drives available now, even if SMART
> tells you a drive is failing, you likely won't have time to copy the
> data over to a new drive before it fails.  On a 18TB drive, using
> pvmove, it can take a long time to move data.

Very true.  This is why I'm essentially running RAID6.  Well, that and
for various reasons you don't want to allow writes to Ceph without at
least one drive worth of redundancy, so having an extra replica means
that you can lose one and remain read-write, and then if you lose a
second during recovery you might be read-only but you still have data
integrity.  (Don't want to get into details - it is a Ceph-specific
issue.)

> I don't even want to think what it would cost to put
> all my 100TBs or so on SSD or NVME drives.  WOW!!!

# kubectl rook-ceph ceph osd df class ssd
ID  CLASS  WEIGHT    REWEIGHT  SIZE     RAW USE  DATA     OMAP
META     AVAIL    %USE   VAR   PGS  STATUS
 8    ssd   6.98630   1.00000  7.0 TiB  1.7 TiB  1.7 TiB   63 MiB  3.9
GiB  5.3 TiB  24.66  1.04  179      up
 4    ssd   1.74660   1.00000  1.7 TiB  465 GiB  462 GiB   16 MiB  2.5
GiB  1.3 TiB  25.99  1.10   45      up
12    ssd   1.74660   1.00000  1.7 TiB  547 GiB  545 GiB   30 MiB  2.1
GiB  1.2 TiB  30.57  1.29   52      up
 1    ssd   6.98630   1.00000  7.0 TiB  1.7 TiB  1.7 TiB   50 MiB  4.2
GiB  5.3 TiB  24.42  1.03  177      up
 5    ssd   6.98630   1.00000  7.0 TiB  1.8 TiB  1.8 TiB   24 MiB  5.0
GiB  5.2 TiB  25.14  1.07  180      up
 3    ssd   1.74660   1.00000  1.7 TiB  585 GiB  583 GiB   18 MiB  2.0
GiB  1.2 TiB  32.70  1.39   57      up
21    ssd   1.74660   1.00000  1.7 TiB  470 GiB  468 GiB   27 MiB  1.9
GiB  1.3 TiB  26.26  1.11   52      up
 9    ssd   1.74660   1.00000  1.7 TiB  506 GiB  504 GiB   11 MiB  2.0
GiB  1.3 TiB  28.29  1.20   49      up
18    ssd   1.74660   1.00000  1.7 TiB  565 GiB  563 GiB   16 MiB  1.7
GiB  1.2 TiB  31.59  1.34   55      up
10    ssd   1.74660   1.00000  1.7 TiB  490 GiB  489 GiB   28 MiB  1.6
GiB  1.3 TiB  27.42  1.16   53      up
22    ssd   1.74660   1.00000  1.7 TiB  479 GiB  478 GiB   19 MiB  1.7
GiB  1.3 TiB  26.80  1.14   50      up
19    ssd  13.97249   1.00000   14 TiB  2.3 TiB  2.3 TiB   87 MiB  5.2
GiB   12 TiB  16.81  0.71  262      up
                        TOTAL   49 TiB   12 TiB   12 TiB  388 MiB   34
GiB   37 TiB  23.61

I'm getting there.  Granted, at 3+2 erasure coding that's only a bit
over 30TiB usable space.

-- 
Rich