Reserved page size in rootdbs
Gabor Fekete asked how reserved pages grow beyond 32 pages in a 14.10 rootdbs, given APAR IT45318 on possible data loss, and whether to lower the bufferpool maxdirty meanwhile. David Williams said extended reserved pages are added when chunks, dbspaces or logical logs are added. Andreas Legner had no further countermeasures and asked which system table was affected. Unresolved.
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Hi I'm looking for some information about the Reserved pages size calculation method. Our customers upraded/upgrading to 14.10FC9 or 14.10FX9W1 and we want to eliminate the risk of data loss. IT45318: POTENTIAL FOR DATA LOSS OR INDEX PROBLEMS IN TABLES LOCATED IN ROOT DBSPACE WHEN EXTENDED RESERVED PAGES ARE IN USE One customers system is currently not meet with the EXTENDED RESERVED PAGES size > 32 criteria, so we think they will safe with upgrading to FC9W1. (only system databases located in the rootdbs) But our question is when will create the engine bigger then 32 page size RESERVED PAGES in the future? I didn't found any resource about this. The customer with 14.10FC9 has a potential risk because we found some RESERVED PAGES witch bigger then 32 pages and the next pages containing some system database data. We will suggest them to upgrade to 14.10.FC10W2, and until they will upgrade to it we will configure the bufferpools maxdirty parameter to very low value. 5 or less. Any good practice or advice to lowering the risk the data lost? ------------------------------ Gábor Fekete Software Engineer Capital Systems Budapest ------------------------------
Hi Gábor, what exactly do you mean by " EXTENDED RESERVED PAGES size > 32 criteria" - it seems your reasoning hinges on this, but I don't see it mentioned in the APAR IT45318 . BR, Andreas ------------------------------ Andreas Legner ------------------------------
Hi Andreas!
There was an IBM notification about this potential data loss almost a month ago and there was a mention about a extented reserved page size criteria.
"How to identify the tables or indexes that are at risk
Examine the output of "oncheck -pe rootdbs" to identify extended reserved page extents that are larger than 32 pages"
Notification and additional details pertaining to APAR IT45318
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Gábor Fekete
Software Engineer
Capital Systems
Budapest
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HI, Extended reserved pages can be added when you add chunks dbspaces logical logs Regards, David. ------------------------------ David Williams ------------------------------
Understanding this criterion now, and I'm afraid the list of counter measures and precautions in that extra article is very exhaustive already and I'd not have any idea beyond that. Since you mentioned " pages containing some system database data" next to such larger extended reserved pages extent, which system table is it that's got its data there? ------------------------------ Andreas Legner ------------------------------