zfs discuss - Jul 2008 - swap & dump on ZFS volume - updated proposal

Hi all,

Based on the further comments I received, following
approach would be taken as far as calculating default
size of swap and dump devices on ZFS volumes in Caiman
installer is concerned.

[1] Following formula would be used for calculating
    swap and dump sizes:

size_of_swap = MAX(512 MiB, MIN(physical_memory/2, 32 GiB))
size_of_dump = MAX(256 MiB, MIN(physical_memory/4, 16 GiB))

User can reconfigure this after installation is done on live
system by "zfs set" command.

[2] dump and swap devices will be considered optional

dump and swap devices will be considered optional during
fresh installation and will be created only if there is
appropriate space available on disk provided.

Minimum disk space required will not take into account
dump and swap, thus allowing user to install on small disks.
This will need to be documented (e.g. as part of release notes),
so that user is aware of such behavior.

Recommended disk size (which now covers one full upgrade plus
2GiB space for additional software) will take into account dump
and swap.

Dump and swap devices will be then created if user dedicates
at least recommended disk space for installation.

Thank you very much all for this valuable input.
Jan

Hello jan,

Tuesday, July 1, 2008, 11:09:54 AM, you wrote:

jd> Hi all,

jd> Based on the further comments I received, following
jd> approach would be taken as far as calculating default
jd> size of swap and dump devices on ZFS volumes in Caiman
jd> installer is concerned.

jd> [1] Following formula would be used for calculating
jd>     swap and dump sizes:

jd> size_of_swap = MAX(512 MiB, MIN(physical_memory/2, 32 GiB))
jd> size_of_dump = MAX(256 MiB, MIN(physical_memory/4, 16 GiB))

jd> User can reconfigure this after installation is done on live
jd> system by "zfs set" command.

jd> [2] dump and swap devices will be considered optional

jd> dump and swap devices will be considered optional during
jd> fresh installation and will be created only if there is
jd> appropriate space available on disk provided.

jd> Minimum disk space required will not take into account
jd> dump and swap, thus allowing user to install on small disks.
jd> This will need to be documented (e.g. as part of release notes),
jd> so that user is aware of such behavior.

jd> Recommended disk size (which now covers one full upgrade plus
jd> 2GiB space for additional software) will take into account dump
jd> and swap.

jd> Dump and swap devices will be then created if user dedicates
jd> at least recommended disk space for installation.

jd> Thank you very much all for this valuable input.
jd> Jan


I like your approach and I like even more that you''ve listened to
community - thank you.


-- 
Best regards,
 Robert Milkowski                            mailto:milek at task.gda.pl
                                       http://milek.blogspot.com

Dave Miner wrote:
> jan damborsky wrote:
> ...
>> [2] dump and swap devices will be considered optional
>>
>> dump and swap devices will be considered optional during
>> fresh installation and will be created only if there is
>> appropriate space available on disk provided.
>>
>> Minimum disk space required will not take into account
>> dump and swap, thus allowing user to install on small disks.
>> This will need to be documented (e.g. as part of release notes),
>> so that user is aware of such behavior.
>>
>
> I''d like to at least consider whether a warning should be
displayed in
> the GUI about the lack of dump space if it won''t be created, since
it
> does represent a serviceability issue.
>
This is a good suggestion - I think we might display the warning message
on Summary screen before user actually starts installation process.
In this case there is possibility to go back and change the disk size.
Or we might display the warning dialog earlier - when user decides to
leave Disk screen.
I will check with Niall and Frank in order to work out the right solution
from UI point of view.

Thank you,
Jan

Hi Robert,

you are quite welcome !

Thank you very much for your comments.

Jan


Robert Milkowski wrote:
> Hello jan,
>
> Tuesday, July 1, 2008, 11:09:54 AM, you wrote:
>
> jd> Hi all,
>
> jd> Based on the further comments I received, following
> jd> approach would be taken as far as calculating default
> jd> size of swap and dump devices on ZFS volumes in Caiman
> jd> installer is concerned.
>
> jd> [1] Following formula would be used for calculating
> jd>     swap and dump sizes:
>
> jd> size_of_swap = MAX(512 MiB, MIN(physical_memory/2, 32 GiB))
> jd> size_of_dump = MAX(256 MiB, MIN(physical_memory/4, 16 GiB))
>
> jd> User can reconfigure this after installation is done on live
> jd> system by "zfs set" command.
>
> jd> [2] dump and swap devices will be considered optional
>
> jd> dump and swap devices will be considered optional during
> jd> fresh installation and will be created only if there is
> jd> appropriate space available on disk provided.
>
> jd> Minimum disk space required will not take into account
> jd> dump and swap, thus allowing user to install on small disks.
> jd> This will need to be documented (e.g. as part of release notes),
> jd> so that user is aware of such behavior.
>
> jd> Recommended disk size (which now covers one full upgrade plus
> jd> 2GiB space for additional software) will take into account dump
> jd> and swap.
>
> jd> Dump and swap devices will be then created if user dedicates
> jd> at least recommended disk space for installation.
>
> jd> Thank you very much all for this valuable input.
> jd> Jan
>
>
> I like your approach and I like even more that you''ve listened to
> community - thank you.
>
>