RE: IDS on AIX 5.2 Offsets? lv types?

Murray, I hate to disagree but I have discovered information in the IBM web-site that refers to the Logical volume control block (Lvcb) being 512 bytes. So why would an 8K offset be needed? I can't get any definitve statement out of IBM tech support. I've called our support company and they have contacted Informix in the UK, but no answer if forthcoming. Is this because they are afraid to make a definitive statement in case they are wrong? Or is it that they just don't know? regards Malcolm --- "Murray Wood (IList)" <ifxmaillist@quanta.co.nz> wrote: > Malcolm > > We have exactly the same issue on AIX. You must use > an offset of 8Kb (I think) for every logical volume > on AIX 5. Its only an issue if you need the AIX > control info - which is required if you have a disk > failure and need to re-mirror the logical volume. > > Similarly at the front of the disk on Solaris, you > cannot use the first disk block (normally 4Kb) as it > contains the disk partition table. Either create > the logical volume from block 1 or use a 4Kb offset. > > MW > > > -----Original Message----- > > From: owner-informix-list@iiug.org > > [mailto:owner-informix-list@iiug.org]On Behalf Of > malcolm weallans > > Sent: Friday, 30 July 2004 3:06 a.m. > > To: informix-list@iiug.org > > Subject: IDS on AIX 5.2 Offsets? lv types? > > > > > > We are running IDS 9.3 on AIX 5.2. We have > discovered > > that on AIX 5.2 the logical volume control block > gets > > corrupted if offset 0 is used. This doesn't > normally > > cause problems until the volume group is exported > and > > imported. > > > > We also have a problem with defining logical > volume > > type. Some installers are setting up the system > with > > the lv type set to jfs whilst others are setting > it to > > raw. > > > > I would welcome any advice on the correct settings > for > > offset and lv type, and more importantly any > advice on > > what I should do to migrate the system to the > correct > > settings. > > > > regards > > > > Malcolm > > sending to informix-list > > sending to informix-list > sending to informix-list

"malcolm weallans" <malcolm.iiug@btopenworld.com> wrote in message news:cel0f5$32f$1@news.xmission.com... > > Murray, > I hate to disagree but I have discovered information > in the IBM web-site that refers to the Logical volume > control block (Lvcb) being 512 bytes. Why does it matter? If 8k has been found to be adequate to circumvent the problem, but you *could* actually get away with less, surely th difference is so small as to be not worth fretting about?

[Top posting .. humm] Why is this an IDS issue, most O/Ses give the complete LV out to aplication usage, the fact the AIX doesn't is an O/S imposed requirement. I too have seen a fair amount of documentation regarding the 512 byte requirement for the LVCB, but perhaps the people to ask would be AIX :) malcolm weallans wrote: > Murray, > I hate to disagree but I have discovered information > in the IBM web-site that refers to the Logical volume > control block (Lvcb) being 512 bytes. So why would an > 8K offset be needed? I can't get any definitve > statement out of IBM tech support. I've called our > support company and they have contacted Informix in > the UK, but no answer if forthcoming. Is this because > they are afraid to make a definitive statement in case > they are wrong? Or is it that they just don't know? > > regards > > Malcolm > > --- "Murray Wood (IList)" <ifxmaillist@quanta.co.nz> > wrote: > Malcolm > >>We have exactly the same issue on AIX. You must use >>an offset of 8Kb (I think) for every logical volume >>on AIX 5. Its only an issue if you need the AIX >>control info - which is required if you have a disk >>failure and need to re-mirror the logical volume. >> >>Similarly at the front of the disk on Solaris, you >>cannot use the first disk block (normally 4Kb) as it >>contains the disk partition table. Either create >>the logical volume from block 1 or use a 4Kb offset. >> >>MW >> >> >>>-----Original Message----- >>>From: owner-informix-list@iiug.org >>>[mailto:owner-informix-list@iiug.org]On Behalf Of >> >>malcolm weallans >> >>>Sent: Friday, 30 July 2004 3:06 a.m. >>>To: informix-list@iiug.org >>>Subject: IDS on AIX 5.2 Offsets? lv types? >>> >>> >>>We are running IDS 9.3 on AIX 5.2. We have >> >>discovered >> >>>that on AIX 5.2 the logical volume control block >> >>gets >> >>>corrupted if offset 0 is used. This doesn't >> >>normally >> >>>cause problems until the volume group is exported >> >>and >> >>>imported. >>> >>>We also have a problem with defining logical >> >>volume >> >>>type. Some installers are setting up the system >> >>with >> >>>the lv type set to jfs whilst others are setting >> >>it to >> >>>raw. >>> >>>I would welcome any advice on the correct settings >> >>for >> >>>offset and lv type, and more importantly any >> >>advice on >> >>>what I should do to migrate the system to the >> >>correct >> >>>settings. >>> >>>regards >>> >>>Malcolm >>>sending to informix-list >> >>sending to informix-list >> > > sending to informix-list