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<DIV dir=ltr align=left><FONT face=Verdana color=#0000ff size=2><SPAN
class=000013314-24102008>Okay. For CLVM it probably makes the most
sense to run one big volume group across your cluster, but there's also the
option of running a non-clustered LVM on each Dom0 host. The latter
would only work for you however if you don't require Xen
migration.</SPAN></FONT></DIV>
<DIV dir=ltr align=left><FONT face=Verdana color=#0000ff size=2><SPAN
class=000013314-24102008></SPAN></FONT> </DIV>
<DIV dir=ltr align=left><FONT face=Verdana color=#0000ff size=2><SPAN
class=000013314-24102008>I see 3 options for central storage in a Xen cluster,
each with their own drawbacks:</SPAN></FONT></DIV>
<DIV dir=ltr align=left><FONT face=Verdana color=#0000ff size=2><SPAN
class=000013314-24102008></SPAN></FONT> </DIV>
<DIV dir=ltr align=left><FONT face=Verdana color=#0000ff size=2><SPAN
class=000013314-24102008>1) Run a single clustered volume group across all
hosts, containing one or more PV's from your shared
storage.</SPAN></FONT></DIV>
<DIV dir=ltr align=left><FONT face=Verdana color=#0000ff size=2><SPAN
class=000013314-24102008></SPAN></FONT> </DIV>
<DIV dir=ltr align=left><FONT face=Verdana color=#0000ff size=2><SPAN
class=000013314-24102008>2) Run a non-clustered volume group on each host,
each with a distinct PV carved out of your shared storage.</SPAN></FONT></DIV>
<DIV dir=ltr align=left><FONT face=Verdana color=#0000ff size=2><SPAN
class=000013314-24102008></SPAN></FONT> </DIV>
<DIV dir=ltr align=left><FONT face=Verdana color=#0000ff size=2><SPAN
class=000013314-24102008>3) Export storage for each host individually from your
SAN, i.e. rely completely on your SAN for volume management. With this you
don't need LVM at all.</SPAN></FONT></DIV>
<DIV dir=ltr align=left><FONT face=Verdana color=#0000ff size=2><SPAN
class=000013314-24102008></SPAN></FONT> </DIV>
<DIV dir=ltr align=left><FONT face=Verdana color=#0000ff size=2><SPAN
class=000013314-24102008>Both 1) and 3) allow you to use Xen migration. 2)
is feasible if you don't need to migrate guests online.</SPAN></FONT></DIV>
<DIV dir=ltr align=left><FONT face=Verdana color=#0000ff size=2><SPAN
class=000013314-24102008></SPAN></FONT> </DIV>
<DIV dir=ltr align=left><FONT face=Verdana color=#0000ff size=2><SPAN
class=000013314-24102008>Our problem with 1) is snapshot support, and that we
could not get pvmove to work acceptably well. (We had to make the entire
volume group inactive before pvmove would even run--I'm not sure if it is
expected, or what we did wrong.)</SPAN></FONT></DIV>
<DIV dir=ltr align=left><FONT face=Verdana color=#0000ff size=2><SPAN
class=000013314-24102008></SPAN></FONT> </DIV>
<DIV dir=ltr align=left><FONT face=Verdana color=#0000ff size=2><SPAN
class=000013314-24102008>We've tried and failed at 1), and will now be
attempting 3). This gives us a lot of flexibility on a storage appliance
that supports snapshots. I'd still like to have pvmove work so we could
migrate online from one SAN to another, if needed, but I haven't been able
to get it to work acceptably well.</SPAN></FONT></DIV>
<DIV dir=ltr align=left><FONT face=Verdana color=#0000ff size=2><SPAN
class=000013314-24102008></SPAN></FONT> </DIV>
<DIV dir=ltr align=left><FONT face=Verdana color=#0000ff size=2><SPAN
class=000013314-24102008>Also I thought I had read that snapshots are not
supported by a clustered LVM? That would be difficult for us
too, as we are relying on snapshots for a backup mechanism.</SPAN></FONT></DIV>
<DIV><FONT face=Verdana color=#0000ff size=2></FONT> </DIV>
<DIV><SPAN class=000013314-24102008><FONT face=Verdana color=#0000ff
size=2>Jeff</FONT></SPAN></DIV>
<DIV><BR></DIV>
<BLOCKQUOTE dir=ltr
style="PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: #0000ff 2px solid; MARGIN-RIGHT: 0px">
<DIV class=OutlookMessageHeader lang=en-us dir=ltr align=left>
<HR tabIndex=-1>
<FONT face=Tahoma size=2><B>From:</B> linux-cluster-bounces@redhat.com
[mailto:linux-cluster-bounces@redhat.com] <B>On Behalf Of </B>Chris
Edwards<BR><B>Sent:</B> Friday, October 24, 2008 10:29 AM<BR><B>To:</B> linux
clustering<BR><B>Subject:</B> RE: [Linux-cluster] Cluster and
LVG/LV<BR></FONT><BR></DIV>
<DIV></DIV>
<DIV class=Section1>
<P class=MsoNormal><SPAN
style="FONT-SIZE: 11pt; COLOR: #1f497d; FONT-FAMILY: 'Calibri','sans-serif'">Yes
to both. Right now the cluster is running GFS and I can migrate VM’s
between the nodes. <o:p></o:p></SPAN></P>
<P class=MsoNormal><SPAN
style="FONT-SIZE: 11pt; COLOR: #1f497d; FONT-FAMILY: 'Calibri','sans-serif'"><o:p> </o:p></SPAN></P>
<P class=MsoNormal><SPAN
style="FONT-SIZE: 11pt; COLOR: #1f497d; FONT-FAMILY: 'Calibri','sans-serif'">This
question is coming up because I have been trying to do a snap shot and I
realized the snapshot is stored on the Volume Group that the LV is located on.
I did not realize this and I cannot do a snapshot because I did
not leave enough space in each of the Volume Groups for each of the
VM’s.<o:p></o:p></SPAN></P>
<P class=MsoNormal><SPAN
style="FONT-SIZE: 11pt; COLOR: #1f497d; FONT-FAMILY: 'Calibri','sans-serif'"><o:p> </o:p></SPAN></P>
<DIV>
<P class=MsoNormal><SPAN
style="FONT-SIZE: 10pt; COLOR: #1f497d; FONT-FAMILY: 'Arial','sans-serif'">---<o:p></o:p></SPAN></P>
<P class=MsoNormal><SPAN
style="FONT-SIZE: 10pt; COLOR: #1f497d; FONT-FAMILY: 'Arial','sans-serif'"><o:p> </o:p></SPAN></P>
<P class=MsoNormal><SPAN
style="FONT-SIZE: 10pt; COLOR: #1f497d; FONT-FAMILY: 'Arial','sans-serif'">Chris
Edwards<BR>Smartech Corp.<BR>Div. of AirNet Group<o:p></o:p></SPAN></P>
<P class=MsoNormal><SPAN
style="FONT-SIZE: 10.5pt; COLOR: #1f497d; FONT-FAMILY: Consolas"><A
href="http://www.airnetgroup.com/">http://www.airnetgroup.com</A><o:p></o:p></SPAN></P>
<P class=MsoNormal><SPAN
style="FONT-SIZE: 10.5pt; COLOR: #1f497d; FONT-FAMILY: Consolas"><A
href="http://www.smartechcorp.net/">http://www.smartechcorp.net</A><o:p></o:p></SPAN></P>
<P class=MsoNormal><SPAN
style="FONT-SIZE: 10pt; COLOR: #1f497d; FONT-FAMILY: 'Arial','sans-serif'"><A
href="mailto:agarrison@smartechcorp.net">cedwards@smartechcorp.net</A><BR>P:
423-664-7678 x114<o:p></o:p></SPAN></P>
<P class=MsoNormal><SPAN
style="FONT-SIZE: 10pt; COLOR: #1f497d; FONT-FAMILY: 'Arial','sans-serif'">C:
423-593-6964<o:p></o:p></SPAN></P>
<P class=MsoNormal><SPAN
style="FONT-SIZE: 10pt; COLOR: #1f497d; FONT-FAMILY: 'Arial','sans-serif'">F:
423-664-7680<o:p></o:p></SPAN></P></DIV>
<P class=MsoNormal><SPAN
style="FONT-SIZE: 11pt; COLOR: #1f497d; FONT-FAMILY: 'Calibri','sans-serif'"><o:p> </o:p></SPAN></P>
<DIV>
<DIV
style="BORDER-RIGHT: medium none; PADDING-RIGHT: 0in; BORDER-TOP: #b5c4df 1pt solid; PADDING-LEFT: 0in; PADDING-BOTTOM: 0in; BORDER-LEFT: medium none; PADDING-TOP: 3pt; BORDER-BOTTOM: medium none">
<P class=MsoNormal><B><SPAN
style="FONT-SIZE: 10pt; FONT-FAMILY: 'Tahoma','sans-serif'">From:</SPAN></B><SPAN
style="FONT-SIZE: 10pt; FONT-FAMILY: 'Tahoma','sans-serif'">
linux-cluster-bounces@redhat.com [mailto:linux-cluster-bounces@redhat.com]
<B>On Behalf Of </B>Jeff Sturm<BR><B>Sent:</B> Friday, October 24, 2008 10:20
AM<BR><B>To:</B> linux clustering<BR><B>Subject:</B> RE: [Linux-cluster]
Cluster and LVG/LV<o:p></o:p></SPAN></P></DIV></DIV>
<P class=MsoNormal><o:p> </o:p></P>
<P class=MsoNormal><SPAN
style="FONT-SIZE: 10pt; COLOR: blue; FONT-FAMILY: 'Verdana','sans-serif'">Chris,</SPAN><o:p></o:p></P>
<P class=MsoNormal> <o:p></o:p></P>
<P class=MsoNormal><SPAN
style="FONT-SIZE: 10pt; COLOR: blue; FONT-FAMILY: 'Verdana','sans-serif'">Are
you running a clustered LVM, and do you expect to be able to use Xen
migration?</SPAN><o:p></o:p></P>
<P class=MsoNormal> <o:p></o:p></P>
<P class=MsoNormal><SPAN
style="FONT-SIZE: 10pt; COLOR: blue; FONT-FAMILY: 'Verdana','sans-serif'">Jeff</SPAN><o:p></o:p></P>
<BLOCKQUOTE
style="BORDER-RIGHT: medium none; PADDING-RIGHT: 0in; BORDER-TOP: medium none; PADDING-LEFT: 4pt; PADDING-BOTTOM: 0in; MARGIN: 5pt 0in 5pt 3.75pt; BORDER-LEFT: blue 1.5pt solid; PADDING-TOP: 0in; BORDER-BOTTOM: medium none">
<P class=MsoNormal><o:p> </o:p></P>
<DIV class=MsoNormal style="TEXT-ALIGN: center" align=center>
<HR align=center width="100%" SIZE=2>
</DIV>
<P class=MsoNormal style="MARGIN-BOTTOM: 12pt"><B><SPAN
style="FONT-SIZE: 10pt; FONT-FAMILY: 'Tahoma','sans-serif'">From:</SPAN></B><SPAN
style="FONT-SIZE: 10pt; FONT-FAMILY: 'Tahoma','sans-serif'">
linux-cluster-bounces@redhat.com [mailto:linux-cluster-bounces@redhat.com]
<B>On Behalf Of </B>Chris Edwards<BR><B>Sent:</B> Friday, October 24, 2008
10:13 AM<BR><B>To:</B> linux clustering<BR><B>Subject:</B> [Linux-cluster]
Cluster and LVG/LV</SPAN><o:p></o:p></P>
<P class=MsoNormal><SPAN
style="FONT-SIZE: 11pt; COLOR: #1f497d; FONT-FAMILY: 'Calibri','sans-serif'">If
I am installing multiple Xen VM’s in a cluster with shared iSCSI space with
Logical Volumes for each virtual machine should I put each LV in its own
logical volume group or should I use one logical volume group for all of the
LV’s?<o:p></o:p></SPAN></P>
<P class=MsoNormal><SPAN
style="FONT-SIZE: 11pt; COLOR: #1f497d; FONT-FAMILY: 'Calibri','sans-serif'"><o:p> </o:p></SPAN></P>
<P class=MsoNormal><SPAN
style="FONT-SIZE: 11pt; COLOR: #1f497d; FONT-FAMILY: 'Calibri','sans-serif'">Thanks!<o:p></o:p></SPAN></P>
<P class=MsoNormal><SPAN
style="FONT-SIZE: 11pt; COLOR: #1f497d; FONT-FAMILY: 'Calibri','sans-serif'"><o:p> </o:p></SPAN></P>
<P class=MsoNormal><SPAN
style="FONT-SIZE: 10pt; COLOR: #1f497d; FONT-FAMILY: 'Arial','sans-serif'">---<o:p></o:p></SPAN></P>
<P class=MsoNormal><SPAN
style="FONT-SIZE: 10pt; COLOR: #1f497d; FONT-FAMILY: 'Arial','sans-serif'"><o:p> </o:p></SPAN></P>
<P class=MsoNormal style="MARGIN-BOTTOM: 12pt"><SPAN
style="FONT-SIZE: 10pt; COLOR: #1f497d; FONT-FAMILY: 'Arial','sans-serif'">Chris
Edwards<o:p></o:p></SPAN></P>
<P class=MsoNormal><SPAN
style="FONT-SIZE: 11pt; COLOR: #1f497d; FONT-FAMILY: 'Calibri','sans-serif'"><o:p> </o:p></SPAN></P>
<P
class=MsoNormal><o:p> </o:p></P></BLOCKQUOTE></DIV></BLOCKQUOTE></BODY></HTML>