On Aug 5, 2009, at 1:06 PM, Martin wrote:
richard wrote:
Preface: yes, shrink will be cool. But we've been
running highly
available,
mission critical datacenters for more than 50 years
without shrink being
widely available.
I would debate that. I remember batch windows and downtime delaying
one's career movement. Today we are 24x7 where an outage can kill
an entire business
Agree.
Do it exactly the same way you do it for UFS. You've
been using UFS
for years without shrink, right? Surely you have
procedures in
place :-)
While I haven't taken a formal survey, everywhere I look I see JFS
on AIX and VxFS on Solaris. I haven't been in a production UFS shop
this decade.
Then why are you talking on Solaris forum? All versions of
Solaris prior to Solaris 10 10/08 only support UFS for boot.
Backout plans are not always simple reversals. A
well managed site will
have procedures for rolling upgrades.
I agree with everything you wrote. Today other technologies allow
live changes to the pool, so companies use those technologies
instead of ZFS.
... and can continue to do so. If you are looking to replace a
for-fee product with for-free, then you need to consider all
ramifications. For example, a shrink causes previously written
data to be re-written, thus exposing the system to additional
failure modes. OTOH, a model of place once and never disrupt
can provide a more reliable service. You will see the latter
"pattern" repeated often for high assurance systems.
There is more than one way to skin a cat.
Which entirely misses the point.
Many cases where people needed to shrink were due to the
inability to plan for future growth. This is compounded by the
rather simplistic interface between a logical volume and traditional
file system. ZFS allows you to dynamically grow the pool, so you
can implement a process of only adding storage as needs dictate.
Bottom line: shrink will be cool, but it is not the perfect solution for
managing changing data needs in a mission critical environment.
-- richard
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