Best Practice for the inplace change from raw devices to cookfiles
Henri Cujass asked for best practice to replace raw devices with cooked files with minimal downtime. Art Kagel said on v14.10 create cooked chunks as mirrors and run the task modify chunk swap_mirror function, then drop the old chunks; older versions need link changes or copying. khaled Bentebal listed mirroring, HDR and ER options and corrected that MIRROR was required until 14.10.xC7. Doug Lawry linked a guide.
Auto-generated by Claude from the posts below — may be imperfect; read the full thread.
Hi Informix DBA's, what's your best practice experience in replacing raw devices with cookfiles in minimum downtime? Mirroring, ER ...? Thanks for every idea. Henri ------------------------------ Henri Cujass leolo IT, CTO Germany IBM Champion henri.cujass@leolo.com ------------------------------
Best practice in v14.10 is to create the new cooked file chunks as mirrors of the original raw chunks, then use the mirror swap API function:
execute function task("modify chunk swap_mirror",<chunk number>).Once that is done you can drop the original raw chunks which are now the mirrors with the new chunk as the primary chunks.
In v12.10 and earlier you have two choices:
If your chunk paths are links, you can drop and recreate the chunk links to point to the new storage and restore the engine from backup - or manually copy the data from the raw chunks to the new cooked file chunks.
If your chunk paths are the physical device "files" corresponding to the raw chunks then your only option is to do a redirected restore to restore to the new chunk files.
In versions earlier than 12.10 only the "drop and recreate the links" choice above is a viable option.
Art
------------------------------
Art S. Kagel, President and Principal Consultant
ASK Database Management Corp.
www.askdbmgt.com
------------------------------
Thank you very much, Art. ------------------------------ Henri Cujass leolo IT, CTO Germany IBM Champion henri.cujass@leolo.com ------------------------------
Hi Henry, The following are some of the solutions possible. A) On the same server, from easier and less dowtime to more complicated and more dowtime 1/ Mirroring - no downtime; if you already have mirroring in place for some of the chunks, you need to reset each individual mirrored chunk first and start mirroring again to the desired cooked file. You have to make sure the instance was intialized to be possibly mirrored (MIRROR=1) 2/ HDR - a slight dowtime ; needs some twicking to be performed because of the names of the chunks. Not as easy as mirroring 3/ Other solutions will have downtime and more complicated to perform ; such as ER, etc. B) On a different server (virtual or physical), from simple to more complicated and more downtime 1/ HDR- a short downtime to reconnect the users. Easy to setup 2/ Others such as ER, etc -- Cordialement, Regards, Khaled Bentebal Directeur G??n??ral - ConsultiX T??l: 33 (0) 1 39 12 18 00 Mobile: 33 (0) 6 07 78 41 97 Email: khaled.bentebal@consult-ix.fr Site Web: www.consult-ix.fr
@Khaled: FYI, in v14.10 MIRROR is always enabled (cannot be turned off any longer) and the MIRROR parameter in the ONCONFIG file is ignored/deprecated. Art ------------------------------ Art S. Kagel, President and Principal Consultant ASK Database Management Corp. www.askdbmgt.com ------------------------------
Art, That is not completely true. You still had to do it up to version 14.10.xC6. Deprecated from 14.10.xC7 on The evolution was easy to do since they only initialized the page in the reserved pages that contains the mirror chunks information (onchek -pr will shwo yhou that or a dump in hex of the 12 reserved pages in the rootdbs chunk). Cordialement, Regards, Khaled Bentebal Directeur Général - ConsultiX Tél: 33 (0) 1 39 12 18 00 Mobile: 33 (0) 6 07 78 41 97 Email: khaled.bentebal@consult-ix.fr Site Web: www.consult-ix.fr Le 15/04/2024 à 13:50, Art Kagel via IBM TechXchange Community a écrit :
You are correct Khaled. Thanks for the correction. Art ------------------------------ Art S. Kagel, President and Principal Consultant ASK Database Management Corp. www.askdbmgt.com ------------------------------
Hi Henri. Here you go! https://www.oninitgroup.com/faq-items/informix-storage-migration-via-mirroring ------------------------------ Doug Lawry Oninit Consulting ------------------------------
Many thanks to everyone for the detailed and quick answers! Best Regards, Henri ------------------------------ Henri Cujass leolo IT, CTO Germany IBM Champion henri.cujass@leolo.com ------------------------------