Re: SWAP question (357 Views)
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Honored Contributor
Michael Steele_2
Posts: 4,934
Registered: ‎08-14-2002
Message 1 of 8 (449 Views)

SWAP question

I have two boxes with Ignite warnings about unknown file system type and both are for 2ndary swap.  They were created without the -C option and are not contiguous.

 

What are the ramafications?

 

Should I remove and recreate?

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Honored Contributor
Bill Hassell
Posts: 14,220
Registered: ‎05-29-2000
Message 2 of 8 (443 Views)

Re: SWAP question

Is the swap volume a raw lvol or filesystem swap? Filesystem swap is really deprecated for today's systems. A raw lvol marked as swap has no filesystem at all, but Ignite should not syntax that (normal) condition. Not sure what -C is referring to. swapon has no -C option. Is your Ignite at least C.7 version?

Honored Contributor
Michael Steele_2
Posts: 4,934
Registered: ‎08-14-2002
Message 3 of 8 (432 Views)

Re: SWAP question

[ Edited ]

Not -C in swapon.  -C is for the Contiguous option in lvcreate.

 

       lvcreate -L 850 -n swap -C y -r n /dev/vg02

 

And contiguous as in , "...the first three lvols of vg00 must be contiguous for the OS to load including lvol2 / primary swap...."

 

Well, this is 2ndary swap that's been added in because lvol2 wasn't big enough and ignite is flagging it.

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Honored Contributor
Bill Hassell
Posts: 14,220
Registered: ‎05-29-2000
Message 4 of 8 (417 Views)

Re: SWAP question

OK. This is fine but -C is not required.

 

>>       lvcreate -L 850 -n swap -C y -r n /dev/vg02

 

The contiguous requirement is only for the first 3 lvols in vg00. Secondary swap can be located anywhere, even in a different VG. There are no restrictions where extra swap can be located. This is because the kernel does not need the extra swap during bootup where there are limited addressing methods available. I assume that you have the extra swap listed in /etc/fstab (required in order to be activated at reboot).

Frequent Advisor
Foolqiu
Posts: 42
Registered: ‎11-14-2008
Message 5 of 8 (395 Views)

Re: SWAP question

How do you write in /etc/fstab. I mean do you replace vxfs with swap?

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Bill Hassell
Posts: 14,220
Registered: ‎05-29-2000
Message 6 of 8 (368 Views)

Re: SWAP question

>> How do you write in /etc/fstab.

 

The man page for fstab is quite useful.

Here is an example:

 

/dev/vg05/myswap3   __swap3__   swap  defaults  0 0

 

where: myswap3 is the lvol, __swap3__ is just a placeholder (not a mountpoint), and swap is the type of data on this lvol.

Honored Contributor
Michael Steele_2
Posts: 4,934
Registered: ‎08-14-2002
Message 7 of 8 (357 Views)

Re: SWAP question

Bill, Bill, Bill.  How the mighty have fallen.  How can you argue with JR Ferg?

 

http://h30499.www3.hp.com/t5/System-Administration/swap/m-p/5346707/highlight/true#M476002

 

I've always made 2ndary swap contigous so this was a surprise for me to see it here.

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Honored Contributor
Bill Hassell
Posts: 14,220
Registered: ‎05-29-2000
Message 8 of 8 (349 Views)

Re: SWAP question

It may be that only Ignite is syntaxing this since I've created a lot of multiple swap areas on lots of systems without -C. On the other hand, I have never checked to see that the extents were not contiguous -- they may have always been contiguous by accident. As mentioned, the primary swap area must be contiguous to be properly handle during bootup. Dump is a different story. The code for dumping is by necessity quite simple and isolated in order to function without OS assistance...

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