RE: Calculations

If you allocate a chunk as 2,048,000 Kbytes, you are requesting 2,048,000 / 4,096 = 512,000 (4K) pages. 2 Gigabytes = 32 * 64 * 1024 * 1024 = 2,147,483,648 = 2,097,152 Kbytes 2 Gigabytes = 2,097,152 / 4 = 524,288 (4K) pages However, you may need to limit your chunk size + offset to 524,287 pages (2,097,148 Kbytes). I have received error messages from Informix utilities, when the chunk size + offset is exactly 2 Gbytes. Two other observations: 1) I would recommend a 4K offset when defining the first chunk on an AIX logical volume. This prevents control information from being overwritten. 2) Define symbolic links for to each AIX logical volume. ln -s /dev/rdata1dbs <symbolic name> Reference the symbolic name when you create your chunks. This technique is recommended by Informix in their documentation and provides more flexibility when, and if, you need to move the data to a different physical location. (I.E. After hardware failures). > -----Original Message----- > From: chris_burton@blue-skies.net [mailto:chris_burton@blue-skies.net] > Sent: Wednesday, November 24, 1999 20:48 > To: informix-list@iiug.org > Subject: Calculations > > > Could someone please verify this for me? > > AIX 4.3 - 4k pages > > Creating chunks: > PP SIZE: 32 megabyte(s) > Create data1dbs chunk of 64 physical partitions. > This should be 2 Gig chunk. > > Then I go into onmonitor to create a new dbspace in this chunk. > > How big can I make this, or what should I type in the size field (k > bytes) to use the entire chunk for this dbspace? > > I think?!?! > > Chunk = 32 * 1024000 * 64 = 2097152000 > Should be able to type in .... > 2048000 > > When I do an onstat -d to look at the space, pages should be 512,000. > If this is correct, please explain the following. And if my > calculation is in error, please help me now. > > onstat -d> > Informix Dynamic Server Version 7.30.UC8 -- On-Line -- Up 02:35:54 > -- 484912 > Kbytes > > Dbspaces > address number flags fchunk nchunks flags owner name > 5058e3c0 21 1 21 10 N informix data27dbs > 19 active, 2047 maximum > > Chunks > address chk/dbs offset size free bpages flags pathname > 5003eb94 2 21 0 517500 1 PO- /dev/rdata1dbs > 5003ec70 3 21 0 517500 512001 PO- /dev/rdata24dbs > 5003ed4c 4 21 0 517500 256001 PO- /dev/rdata2dbs > 5003f198 9 21 0 517500 1 PO- /dev/rdata3dbs > 5003f350 11 21 0 517500 88113 PO- /dev/rhist_data3_2 > 5003fbe8 21 21 0 512000 120827 PO- /dev/rdata27dbs > 50065a28 25 21 0 512000 486405 PO- /dev/rdata27dbs_2 > 50065b04 26 21 0 512000 384005 PO- /dev/rdata27dbs_3 > 50070b98 35 21 0 517500 517497 PO- /dev/rhist_data3_14 > 50071a34 52 21 0 517500 1 PO- /dev/rhist_data2 > > These are NOT all on the same devices. It is RAID5. > lspv -l <device> > data1dbs 64 64 64..00..00..00..00 N/A > data24dbs 64 64 00..64..00..00..00 N/A > data2dbs 64 64 00..64..00..00..00 N/A > data3dbs 64 64 00..64..00..00..00 N/A > hist_data3_2 64 64 00..00..00..64..00 N/A > data27dbs 64 64 64..00..00..00..00 N/A > data27dbs_2 64 64 00..00..64..00..00 N/A > data27dbs_3 64 64 00..00..42..22..00 N/A > hist_data3_14 64 64 04..60..00..00..00 N/A > hist_data2 64 64 00..00..00..50..14 N/A >