Long-time maintenance of Hammer2 on HDD

Mikhail Novosyolov m.novosyolov at rosalinux.ru
Sat Nov 9 16:46:46 PST 2019

In such case it would we strange if there was degradation. But I meant a 
situation when there are a lot of snapshots in the filesystem on HDD, 
many of which are created and deleted, for example increment hourly 
backups of a database. This will cause fragmentation to my mind. 
Fragmentation will not have effect of a SSD, but will have it on HDD. My 
question was how does H2 handle fragmentation and defragmentation and 
does it happen on H2.

09.11.2019 20:47, Justin Sherrill пишет:
> synth is here:
> https://github.com/jrmarino/synth
> dsynth is in DragonFly:
> https://gitweb.dragonflybsd.org/dragonfly.git/tree/HEAD:/usr.bin/dsynth
> But I don't think either is doing any Hammer-specific actions.  My
> note was that just using the filesystem doesn't seem to cause problems
> over time.
> On Fri, Nov 8, 2019 at 10:29 PM Mikhail Novosyolov
> <m.novosyolov at rosalinux.ru> wrote:
>> Are those scripts available in public? It would be interesting to look
>> at examples how Hammer snapshots are managed.
>> 08.11.2019 20:28, Justin Sherrill пишет:
>>> For what it's worth, the many, many bulk builds of dports using
>>> poudriere and synth and dsynth are happening on hammer/hammer2 disks,
>>> and to my knowledge, there has been no degradation over time.
>>> On Thu, Nov 7, 2019 at 5:18 PM Mikhail Novosyolov
>>> <m.novosyolov at rosalinux.ru> wrote:
>>>> As far as I understand, Hammer2 was designed mainly for flash memory (SSD, NVMe).
>>>> Currently I am using it on a 2 TB HDD.
>>>> Imagine that a lot of files and snapshots are created and deleted and there are multiple MySQL databases there.
>>>> How will Hammer2 consistency and performance degrade over time in this use case?
>>>> Did not find information about HDDs and defragmentation in sys/fs/Hammer2/DESIGN.

More information about the Hammer mailing list