RAM speedup

Rupert Gallagher ruga at protonmail.com
Tue Jun 30 11:52:28 UTC 2020

‐‐‐‐‐‐‐ Original Message ‐‐‐‐‐‐‐
On Sunday 28 June 2020 21:29, Matthias Schniedermeyer <ms at citd.de> wrote:

> On 28.06.2020 16:46, Rupert Gallagher wrote:
> > ????????????????????? Original Message ?????????????????????
> > On Sunday 28 June 2020 13:58, Matthias Schniedermeyer ms at citd.de wrote:
> > destination:
> > ST5000LM000-2AN1 sata hdd
> > Writing speed : 74 MB/s
> > Reading speed : 89 MB/s
> And this HDD is a SMR model(*) on top of beeing a 4k sector model emulating 512 byte sectors.
> So alignment needs to be correct and the filesystems must use 4k sectors.
> This HDD is NOT suitable for beeing used for small files and a hardlink-farm.
> SMR HDDs only reach best performance if used "like a tape drive" with large and linear writing.
> I use SMR HDDs myself and only use them for "really large" files (>500MB per file), otherwise they perform very poorly.
> I also align my partitions correctly and set XFS to "4k sector"-size.
> Which nowadaya means: I use 4k sectors for anything. As i only have been
> using 4k sector HDDs for nearly as long as they are on the market (IIRC >1 decade).
> Also SSDs are usually optimized for 4k sectors too.
> *:
> https://en.wikipedia.org/wiki/Shingled_magnetic_recording

SMR is the cost we pay for large storage on small space.
There is something similar to SMR also for SSD, found in Samsung QVO units.

The cost-benefit analysis for 2.5" drives led to this product.

Costs are HDD <= SSD < TAPE (HP LTO Ultrium).

We are using this disk "like a tape drive", with hardlinks because it can.

This is from the current disklabel:

bytes/sector: 512
sectors/track: 255
tracks/cylinder: 511
sectors/cylinder: 130305
cylinders: 74959
total sectors: 9767541168 # total bytes: 4.5T

This is from the current ffs2:

fs block size      : 8192 bytes
Free disk space    : 4713572474880 bytes

The values are native, without any tuning.

However, the bottom line is that I get the job done in 2 hours via the lan, and 8 hours via the bus...

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