Hi,
From my question:
>I want to partition a RZ29B disk for use by a SYBASE as raw database partitions.
>We have certain sizes for the partitions we want to create. I know you should
>not put a swap partiton that starts with sector '0' say, start/end = 0/131071,
>otherwise it could overwrite the disk label.
>
>Would the disklabel be wiped out if a put a SYBASE partion for the range 0/532480 ??
>
>If this is the case, is it safe to create a partition starting at sector '1' like
>1/532480 ?? Or is this to close to sector '0' ??
I got the following responses:
hawkeye_at_SpiritOne.com (Gary C. Jenkins)
>Allocate 512 for a and start b at 512. Something like the following:
>
>Partition Size Start
>
>a 512 0
>b 131071 512
>c 8XXXXX 0
>
>This will provide the necessary space for the disk label. With V3.X and V4.X
>the size of this label information is larger and should always be provided for
>either through a separate partition, as above, or by increasing the size of the
>a partition.
alan_at_nabeth.cxo.dec.com (Alan Rollow - Dr. File System's Home for Wayward Inodes.)
>Unless Sybase makes an effort not to use the first sector of a
>partition, it will probably try to use that sector, overwriting
>the label. Making a partition one sector long for to protect
>the label is probably safe. Using 8 KB is certainly safe.
>
>It is worth noting that to edit the partition table you need
>two partitions that start at the beginning of the disk. Be
>careful how to repartition or you may get semi-permanently
>stuck with that partition table.
"Juergen Bock" <FDV20_24_at_dbf-s1.dbf.ddb.de>
>I posted the same problem a while ago. There were a bazillion
>responses. Each says something different; at least the DEC gurus
>claim you can use cyl 0 (with DUnix). Nobody knows about Sybase.
>Anyway, you can find the responses I received at
>http://www.ornl.gov/cts/archives/mailing-lists/alpha-osf-managers/1996/09/msg00027.html
>and a followup at
>http://www.ornl.gov/cts/archives/mailing-lists/alpha-osf-managers/1996/09/msg00083.html
>
>To make sure nothing bad happens we don't use cyl 0. Sybase doesn't
>care where the partitions are physically on the disk. So I think you
>can create a small partition from cyl 0 to 1. The loss is minimal.
davis_at_decatl.alf.dec.com
> By convention DU suggests starting raw partitions at
>block 16 to ensure that the disklabel doesn't get stomped on.
Jeff Stelzner <jeffs_at_esca.com>
>Joe - This is an ideal situation to use LSM. You can size the partitions [LSM
>volumes] any way you want, LSM will avoid portions of the disk, and you can
>resize on the fly when database requirements change. This can be done with the
>basic LSM facilities, no extra license required. If you want to do mirroring,
>use Sybase for that purpose.
Lucien_HERCAUD_at_paribas.com (Lucien HERCAUD)
> No partition except the "system" ones shall start at offset ZERO!
>
> So, the rule we shall apply is to use sector 16 or 32 as the start of your
> partition. This is not a big lost of space !!!
From all of this, having RAW partitions used by SYBASE databases it would be safe
to keep clear of 'cyl 0' - possibly start from 'cyl 1' ???. Gary C. Jenkins suggests
starting RAW partitions at 'cyl 512' as the size of this label information is larger
for DUV3 & 4 systems.
Everyone has differing opinions, so to be safe than sorry I will start it far away
as possible depending on the sizes I require for the partitions.
Thanks to all
Joe Spanicek
joe_at_resptk.bhp.com.au
Received on Wed Oct 30 1996 - 23:30:37 NZDT