Re: [gentoo-user] Getting maximum space out of a hard drive

[Dale]

Rich Freeman wrote:
> On Sat, Aug 20, 2022 at 3:15 PM Dale <rdalek1967@×××××.com> wrote:
>> Related question.  Does encryption slow the read/write speeds of a drive
>> down a fair amount?  This new 10TB drive is maxing out at about
>> 49.51MB/s or so.
> Encryption won't impact the write speeds themselves of course, but it
> could introduce a CPU bottleneck.  If you don't have any cores pegged
> at 100% though I'd say this isn't happening.  On x86 encrypting a hard
> drive shouldn't be a problem. I have seen it become a bottleneck on
> something like a Pi4 if the encryption isn't directly supported in
> hardware by the CPU.
>
> 50MB/s is reasonable if you have an IOPS-limited workload.  It is of
> course a bit low for something that is bandwidth-limited.  If you want
> to test that I'm not sure rsync is a great way to go.  I'd pause that
> (ctrl-z is fine), then verify that all disk IO goes to zero (might
> take 30s to clear out the cache).  Then I'd use "time dd bs=1M
> count=20000 if=/dev/zero of=/path/to/drive/test"  to measure how long
> it takes to create a 20GB file.  Oh, this assumes you're not using a
> filesystem that can detect all-zeros and compress or make the file
> sparse.  If you get crazy-fast results then I'd do a test like copying
> a single large file with cp and timing that.
>
> Make sure your disk has no IO before testing.  If you have two
> processes accessing at once then you're going to get a huge drop in
> performance on a spinning disk.  That includes one writing process and
> one reading one, unless the reads all hit the cache.
>

Kinda picking random reply. 

I finally got the full backups done and have updated a couple times, new
drive and old drives.  Someone mentioned atop and I gave it a try.  I
noticed the drive parts that is either being read from or written to
show up in red and a high amount of use.  After doing some google
searching, red means really, really busy.  Makes sense.  So, the drives
are apparently just maxing out. 

I also noticed something else.  Given that my internet is so much faster
now, that also puts a load on disk I/O.  Heck, the internet alone can
almost max out the drive I/O.  On top of that I'm watching a video on my
TV.  So, doing backups, watching TV and downloading stuff over a really
fast internet connection, no wonder things were a little slow. 

I also ran this on the new 10TB drive and a older SMR 8TB drive.  This
is about normal, ish.  sdl is the 8TB and sdm is the 10TB. 


root@fireball / # hdparm -tT /dev/sdl

/dev/sdl:
 Timing cached reads:   8814 MB in  2.00 seconds = 4410.88 MB/sec
 Timing buffered disk reads: 558 MB in  3.00 seconds = 185.76 MB/sec
root@fireball / # hdparm -tT /dev/sdm

/dev/sdm:
 Timing cached reads:   8992 MB in  2.00 seconds = 4499.72 MB/sec
 Timing buffered disk reads: 612 MB in  3.01 seconds = 203.47 MB/sec
root@fireball / #

I have some other drives that are slower and a couple that are faster. 
So, I guess it about averages out. 

I have another question.  I notice that the drive activity light stays
on a lot more, downloading/uploading faster etc etc.  Will that cause my
drives to age faster or is that designed in?  I try to get the higher
grade of drives, avoid those built for light duty stuff.  Of course,
they not designed to be used by NASA either.  :/

By the way, that new backup drive, filling up fast.  My storage
partition is too.  This fast internet is causing, issues.  ROFL  Time to
hunt up a deal on another 8TB or 10TB drive to add on.  Dang, my case is
about full.  I really need a NAS or something.  :-D

Dale

:-)  :-)