Re: ALTER DATABASE ARCHIVELOG COMPRESS ENABLE

Andy, thanks for the reply.

As far I researched ACFS compression option is supported for all databases files. It just doesn't work (it's null!) for online redo logs and control files.

In other words: online redo logs and control file are never compressed, even when stored into a compressed on ACFS filesystem. This is not a problem, as these files are, in general, a small fraction of the database full storage. And this is reasonable, as these files must have small, fast and synced writes. Not the ideal environment for an on-the-fly compression.

By the way, I'm interested now just in compression for archived redo logs, which large, async, once write batch are, IMHO, perfect for on-the-fly compression.

Thanks anyway for enrich the conversation.

*--*
*Att*

*Luis Santos*

Em sex, 21 de dez de 2018 às 14:50, Andy Wattenhofer <watt0012_at_umn.edu> escreveu:

> For the sake of completeness, it appears that ACFS compression *is*
> supported for database files. I had to check, because some ACFS features
> are not supported for database files where there is a paid alternative
> option such as Database Vault. See the full list in the chart here (scroll
> down to the ACFS row):
> https://docs.oracle.com/database/121/DBLIC/editions.htm#GUID-75262092-CD86-4B30-A21B-92ECC1C2E130
>
>
> Andy
>
> On Fri, Dec 21, 2018 at 6:41 AM Luis Santos <lsantos_at_pobox.com> wrote:
>
>> Niall, thanks for your input.
>>
>> I was just researching about it just after I have sent my previous email.
>>
>> http://afatkulin.blogspot.com/2017/07/122-acfs-compression-part-i.html
>>
>> Yes, this can be a reasonable solution. And supported too!
>>
>> I just can't figure out why compression is just an ACFS option. Why not
>> also a Disk Group attribute?
>>
>>
>> *--*
>> *Att*
>>
>>
>> *Luis Santos*
>>
>>
>>
>> Em sex, 21 de dez de 2018 às 10:04, <niall.litchfield_at_gmail.com>
>> escreveu:
>>
>>> In the case of ASM you could always provision an ACFS filesystem which
>>> also supports compression since 12.2,:). I'd be wary of using a feature
>>> that's been around since 10 and never made it to documented status when
>>> there are supported alternative options.
>>>
>>> On Fri, Dec 21, 2018 at 10:26 AM Luis Santos <lsantos_at_pobox.com> wrote:
>>>
>>>> I'm aware of on-the-fly compression filesystems since old Windows
>>>> Stacker.
>>>>
>>>> This is not an option for Oracle DBs in ASM.
>>>>
>>>> But thanks anyway!
>>>>
>>>>
>>>> *--*
>>>> *Att*
>>>>
>>>>
>>>> *Luis Santos*
>>>>
>>>>
>>>>
>>>> Em qui, 20 de dez de 2018 às 17:01, Mladen Gogala <
>>>> gogala.mladen_at_gmail.com> escreveu:
>>>>
>>>>> Ah that!
>>>>>
>>>>> That too is supported:
>>>>>
>>>>> https://www.redhat.com/en/blog/look-vdo-new-linux-compression-layer
>>>>>
>>>>> You can have a compressed file system and put your archive logs there.
>>>>> NTFS too has such capability. There is no reason for Oracle to do
>>>>> compression of the archive logs. I prefer rman to maintain cleanliness of
>>>>> my LOG_ARCHIVE_DEST_1. And cleanliness is next to godliness.
>>>>>
>>>>> Regards
>>>>>
>>>>>
>>>>> On 12/20/18 1:16 PM, Luis Santos wrote:
>>>>>
>>>>> This relates to on-the-fly compression on redo log transport between
>>>>> Data Guard DB nodes.
>>>>>
>>>>> --
>>>>> Mladen Gogala
>>>>> Database Consultant
>>>>> Tel: (347) 321-1217
>>>>>
>>>>>
>>>
>>> --
>>> Niall Litchfield
>>> Oracle DBA
>>> http://www.orawin.info
>>>
>>

--
http://www.freelists.org/webpage/oracle-l