RE: Can Disk mirroring/db snapshots replace the usage oftaking database backups?



"Sebastian, Norma
J."
<NormaJean.Sebast To
ian@xxxxxxxxxxx> <jpierrot@xxxxxxxxx>
cc
04/11/2008 04:38 <informix-list-bounces@xxxxxxxx>,
PM <informix-list@xxxxxxxx>
Subject
RE: Can Disk mirroring/db snapshots
replace the usage oftaking
database backups?













JP,

if your assumption is right that it uses an "onmode -c block" then you
would have a recoverable/rollforwardable image....
IF anything goes wrong during the time the snapshot is taken.... then
everybody waits till it is fixed... cuz the DB is blocked... this would
appear to be no different than you yourself issuing the block/unblock
commands... but if the auto-software (falconstor) introduced between the
block/unblock goes haywire for any reason... well... there u are...
blocked.. and so are your users.... it would be wise at the least to build
some type of monitoring/page-out to DBAs in the process in the event there
is a snag and a manual unblock is needed. (this falconstor should be able
to page-out on that)

K

if the software builds in a block/unblock... then it is still in your best
interest to back up the DB logs via informix onbar because it will be
onbar, not falconstor, restoring/rolling those logs forward. (same with
RMAN i would guess)

I might still have to backup the db and logs not as frequent as I do today,
maybe like every 2 weeks.

how big is your database?...
--- about 200GB

how is this software going to make your life any easier?
-------We do a lot of data refresh from prod, but with this technology, we
are promised quicker refreshes since we would not have to restore the data.

what prevents you from scripting a block/split/unblock yourself today
without this software?...
Right now, there is no need for me to do it, I am fine with point in time
restore features built in IDS.

is this software being pushed on you by management?
We were outsourced to company XYZ and they cannot deliver an acceptable TSM
solution. We ended up with something that works but it is too lengthy since
it is done over the wire. The other option requires a local TSM server and
a remote server to create some sort of redundancy within the process but
the cost may be to high for whomever to bear. So we were presented with
this FalconStor solution to make ends meet.

i only have 2 brain cells, but i can't imagine any value in adding this to
an IDS system.
do they really really support IDS or is that only lip service because they
want u to buy it for oracle and/or sqlserver or something?...

some, if not all of your questions should be posed to falconstor.... if
they truly support informix, they should be able to answer your concerns.
if they really want your business, they should help u set it up for free on
a free test server to see the value....


i searched their web site for informix, it came up with 2 tiny
references... one in legal smallprint and the other in a news article....
but if you search for oracle or sql server on their site... .. sqlserver
has 2 pages of references and oracle has 3 pages.

so they really support informix? put the ball in their court to prove
it...
They said they are certified for Informix 9 not 7 yet, and they will get
that certification if needed since the Prod environment still on 7.31.UD8.
Everything will be on 10 sometimes this year, so they will surely attain
that certification in order to support our environment. Same scenario with
the OS, I don't think they are certified yet for Informix on AIX platform
5.2 and 5.3


sorry... feeling critical today...
Norma Jean





From: informix-list-bounces@xxxxxxxx
[mailto:informix-list-bounces@xxxxxxxx] On Behalf Of jpierrot@xxxxxxxxx
Sent: Friday, April 11, 2008 1:42 PM
To: Kevin Cherkauer
Cc: informix-list-bounces@xxxxxxxx; informix-list@xxxxxxxx
Subject: Re: Can Disk mirroring/db snapshots replace the usage oftaking
database backups?



There are a few things I need to add to this post:
According to the vendor, FalconStor has a built in snapshot agent for
Informix which forces Informix to flush all information to disk and inserts
a tag into the data stream being written to disk (presumably at the end of
the data being flushed and in front of any new data), per se, the snapshot
is consistent as of that point in time. Any update after that doesn't
impact the snapshot data.

I do not know yet how the snapshot agent triggers Informix to flush
everything to disk, but assuming it somehow forces it with an onmode -c..
(block). Not sure on how they do it.

Based on the frequency level to capture the snapshot, is there any impact
on users and environments?

Do you see any impact with this Agent on the database environment and users
and how does the database instance start to use this disk?

Additionally, the Snapshot Agent uses an Informix API that isn't in 7 but
was introduced in 9.

Any feedback and comments on all the above would be greatly appreciated

Regards,

jp


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