On 09/11/2014 02:04 AM, swadm wrote:[color=blue]
[SLES 11 SP3, LVM2, lvm2-2.02]
Is there any recommendation / best practice guide on the design of
how many should I have?[/color]
All I know is the minimum number: 1.
Currently we have two vgs to 6 TB each.
In the need of additional 6 TB - what are the pros and cons of creating
another vg or growing the existing ones.
As the PVs are actually VMWare vdisks, the distribution of the RAID
based storage is flexible with a two vg design, already.[/color]
I suppose it depends on your needs. If you want to expand an existing
logical volume (LV), then adding new disks to a new volume group (VG) will
definitely not help you at all, so instead add new Physical Volumes (PV)
to existing VG so space is available to expand existing LV. If you want
to create new LVs, then new VGs are an option, though without a reason to
do that I am not sure why you would as a rule.
There may be reasons to add new LVs to new VGs which are being created
from higher or lower-end PVs; for example, you have your system working
today and you want to bring on some new super-fast storage for a
mission-critical application. Rather than adding your new fast disks (PV)
to an existing VG which also has existing slow disks, add them to a new VG
and then create a new LV from that and mount it somewhere like
/mnt/superfast or whatever. The same would apply if you were adding new,
but low-end (inexpensive) storage to a system, keeping it separate from
the existing storage powering an otherwise expensive system.
As usual, the answer is, “It depends.” Welcome to IT.
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