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- From: julie@levell.austin.ibm.com (Julie L. Craft)
- Newsgroups: comp.unix.aix
- Subject: Re: SCSI disk and volume group problems
- Keywords: jfs i-nodes filsystem
- Message-ID: <1992Sep4.221148.1030@awdprime.austin.ibm.com>
- Date: 4 Sep 92 22:11:48 GMT
- References: <1992Sep3.154851.26029@menudo.uh.edu>
- Sender: news@awdprime.austin.ibm.com (USENET News)
- Organization: IBM, Austin
- Lines: 65
-
- In article <1992Sep3.154851.26029@menudo.uh.edu> twyang@cs.uh.edu (Tien-Wan Yang) writes:
- > stuff deleted...
- >So I tried to partition the two SCSI disks into 2 volume groups; each volume
- >group on a single physical volume. I have the following questions:
- >
- > 1. What is the major number for a volume group on a SCSI disk?
-
- Please don't worry about major numbers,
- mkvg will automatically generate a major number for you,
- based on what is available in the /etc/objrepos/CuDvDr class.
- It uses an internal command called lvgenmajor which uses
- genmajor() from libcfg.a.
-
- You don't have to give it a major number. The only people
- who need to worry about major numbers are HANFS people,
- or other who use twin-tailed disks.
-
- > 2. Should I use the same major number or different major number for
- > different volume group on SCSI disk?
-
- Yes! Again, mkvg and importvg will take care of this
- for you.
-
- > 3. If a volume group has 2 physical volumes, is it reliable to interleave
- > a logical volume on these 2 disks?
-
- Yup, in fact it helps performance wise, but may hurt if
- you lose one disk, you've basically lost the whole logical
- volume.
-
- >
- >I already ran into trouble: I specified a volume group on a SCSI disk with
- >major number 17. It works. I specified another volume group with major
- >number 19. It failed. When I tried to delete this failed volume group, I
- >failed again and got the following message:
-
- It probably failed because 19 was being used:
- ls -l /dev/* |grep 19
- >
- > 0516-044 lqueryvg: The write to internal map file failed. Confirm
- > space is available under the filesystem directory /etc then
- > execute varyonvg again.
- > 0516-882 reducevg: Unable to reduce volume group.
- >
- That means you need to increase your / filesytem. Each volume
- group can take up to 1meg of space in / when it creates the
- map file if you leave the default of 32 PV's. If you specify
- a smaller number with the -d option for mkvg, the map file
- will be smaller.
-
- >I looked through info but couldn't find any helpful information. Can someone
- >help. Any hint or suggestion will be appreciated. Thanks in advance.
- >
- >Tien-wan Yang twyang@cs.uh.edu
- >
-
- Later,
- Julie
-
-
- --
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- Julie Levell Craft IBM AUSTIN,TX Internet: julie@aixwiz.austin.ibm.com
- IBMNET: JULIEL at AUSVM6 2F-007/903 (512) 838-2677 (Tie 678-2677)
- "I'm not getting defensive!"
-