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List: aix-l
Subject: Re: ??: Disks used by LV
From: "Green, Simon" <Simon.Green () EU ! ALTRIA ! COM>
Date: 2004-07-22 13:21:54
Message-ID: D4AE64E989E7D411A8540001FAD48E2D16F64812 () kjsgbcheshrexc2 ! eu ! pm ! com
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It's theoretically possible that LVM would choose to allocate partitions on
hdisk2 first, then hdisk1. This could get messy! Doing two extendlvs would
prevent that, but it's also possible to prevent it by specifying an
inter-volume allocation of "minimum", which will force LVM to allocate on
the existing disk(s) before extending onto another disk.
My preferred solution when disk placement is important is to use a map.
e.g.
hdisk1:400-537
hdisk2:1-100
Then... extendlv -m <map_file> lv_name 238
Your map_file can cover more PPs than you actually want, but not less. The
partitions will be used in the order in which they are listed. All of the
PPs listed must be unallocated, so if there were one odd partition used in
the middle of a range, you'd have to split it into two.
e.g.
hdisk2:1-40
hdisk2:42=101
If you're careful with your intra- and inter-volume allocation policies this
isn't usually necessary, but sometimes it's nice to be sure what's going on.
I've seen LVM do strange things when extending LVs from time to time. Use
of maps is ESPECIALLY important if you're mirroring, IMHO.
--
Simon Green
Altria ITSC Europe Ltd
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-----Original Message-----
From: Kumar, Praveen (cahoot) [mailto:Praveen.Kumar@CAHOOT.COM]
Sent: 22 July 2004 13:03
To: aix-l@Princeton.EDU
Subject: Re: ??: Disks used by LV
Ok do you want me to give both the hdisk numbers in one go. something like
this
extendlv lv_name <no of LP's> hdisk1 hdisk2..
isn't it?
So this uses the available disk space on hdisk1 first and the for the
remaining space it picks up from the next given disk. Right.
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<DIV><SPAN class=910001313-22072004><FONT face=Arial color=#0000ff size=2>It's
theoretically possible that LVM would choose to allocate partitions on hdisk2
first, then hdisk1. This could get messy! Doing two extendlvs would
prevent that, but it's also possible to prevent it by specifying an inter-volume
allocation of "minimum", which will force LVM to allocate on the existing
disk(s) before extending onto another disk.</FONT></SPAN></DIV>
<DIV><SPAN class=910001313-22072004><FONT face=Arial color=#0000ff size=2>My
preferred solution when disk placement is important is to use a
map.</FONT></SPAN></DIV>
<DIV><SPAN class=910001313-22072004><FONT face=Arial color=#0000ff
size=2>e.g.</FONT></SPAN></DIV>
<DIV><SPAN class=910001313-22072004><FONT face=Arial color=#0000ff
size=2>hdisk1:400-537</FONT></SPAN></DIV>
<DIV><SPAN class=910001313-22072004><FONT face=Arial color=#0000ff
size=2>hdisk2:1-100</FONT></SPAN></DIV>
<DIV><SPAN class=910001313-22072004><FONT face=Arial color=#0000ff
size=2></FONT></SPAN> </DIV>
<DIV><SPAN class=910001313-22072004><FONT face=Arial color=#0000ff
size=2>Then... extendlv -m <map_file> lv_name
238</FONT></SPAN></DIV>
<DIV><SPAN class=910001313-22072004><FONT face=Arial color=#0000ff
size=2></FONT></SPAN> </DIV>
<DIV><SPAN class=910001313-22072004><FONT face=Arial color=#0000ff size=2>Your
map_file can cover more PPs than you actually want, but not less. The
partitions will be used in the order in which they are listed. All of the
PPs listed must be unallocated, so if there were one odd partition used in the
middle of a range, you'd have to split it into two. </FONT></SPAN></DIV>
<DIV><SPAN class=910001313-22072004><FONT face=Arial color=#0000ff size=2>e.g.
</FONT></SPAN></DIV>
<DIV><SPAN class=910001313-22072004><FONT face=Arial color=#0000ff
size=2>hdisk2:1-40</FONT></SPAN></DIV>
<DIV><SPAN class=910001313-22072004><FONT face=Arial color=#0000ff
size=2>hdisk2:42=101</FONT></SPAN></DIV>
<DIV><SPAN class=910001313-22072004><FONT face=Arial color=#0000ff
size=2></FONT></SPAN> </DIV>
<DIV><SPAN class=910001313-22072004><FONT face=Arial color=#0000ff size=2>If
you're careful with your intra- and inter-volume allocation policies this isn't
usually necessary, but sometimes it's nice to be sure what's going on.
I've seen LVM do strange things when extending LVs from time to time. Use
of maps is ESPECIALLY important if you're mirroring, IMHO.</FONT></SPAN></DIV>
<DIV><SPAN class=910001313-22072004><!-- Converted from text/rtf format -->
<P><SPAN lang=en-gb><FONT face="Courier New" size=2>-- </FONT></SPAN><BR><SPAN
lang=en-gb><FONT face="Courier New" size=2>Simon Green</FONT></SPAN> <BR><SPAN
lang=en-gb><FONT face="Courier New" size=2>Altria ITSC Europe Ltd</FONT></SPAN>
</P>
<P><SPAN lang=en-gb><FONT face="Courier New" size=2>AIX-L Archive at <A
href="https://new-lists.princeton.edu/listserv/aix-l.html">https://new-lists.princeton.edu/listserv/aix-l.html</A></FONT></SPAN> \
</P>
<P><SPAN lang=en-gb><FONT face="Courier New" size=2>New to AIX? <A
href="http://publib-b.boulder.ibm.com/redbooks.nsf/portals/UNIX">http://publib-b.boulder.ibm.com/redbooks.nsf/portals/UNIX</A></FONT></SPAN> \
</P>
<P><SPAN lang=en-gb><FONT face="Courier New" size=2>N.B. Unsolicited email from
vendors will not be appreciated.</FONT></SPAN> <BR><SPAN lang=en-gb><FONT
face="Courier New" size=2>Please post all follow-ups to the list.</FONT></SPAN>
</P></SPAN></DIV>
<BLOCKQUOTE
style="PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: #0000ff 2px solid; \
MARGIN-RIGHT: 0px"> <DIV></DIV>
<DIV class=OutlookMessageHeader lang=en-us dir=ltr align=left><FONT
face=Tahoma size=2>-----Original Message-----<BR><B>From:</B> Kumar, Praveen
(cahoot) [mailto:Praveen.Kumar@CAHOOT.COM] <BR><B>Sent:</B> 22 July 2004
13:03<BR><B>To:</B> aix-l@Princeton.EDU<BR><B>Subject:</B> Re: ??: Disks used
by LV<BR><BR></FONT></DIV>
<DIV><SPAN class=593130112-22072004><FONT face=Arial color=#0000ff size=2>Ok
do you want me to give both the hdisk numbers in one go. something like
this</FONT></SPAN></DIV>
<DIV><SPAN class=593130112-22072004><FONT face=Arial color=#0000ff
size=2></FONT></SPAN> </DIV>
<DIV><SPAN class=593130112-22072004><FONT face=Arial color=#0000ff
size=2>extendlv lv_name <no of LP's> hdisk1 hdisk2..</FONT></SPAN></DIV>
<DIV><SPAN class=593130112-22072004><FONT face=Arial color=#0000ff
size=2></FONT></SPAN> </DIV>
<DIV><SPAN class=593130112-22072004><FONT face=Arial color=#0000ff
size=2>isn't it?</FONT></SPAN></DIV>
<DIV><SPAN class=593130112-22072004><FONT face=Arial color=#0000ff
size=2></FONT></SPAN> </DIV>
<DIV><SPAN class=593130112-22072004><FONT face=Arial color=#0000ff size=2>So
this uses the available disk space on hdisk1 first and the for the
remaining space it picks up from the next given disk.
Right.</FONT></SPAN><CODE><FONT
size=3></DIV></BLOCKQUOTE></FONT></CODE></BODY></HTML>
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