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From: Ron Johnson <ron.l.johnson@cox.net>
To: linux-lvm@redhat.com
Subject: Re: [linux-lvm] Powerfailure and snapshot consistency
Date: Sat, 26 Mar 2011 00:25:41 -0500	[thread overview]
Message-ID: <4D8D78D5.7050701@cox.net> (raw)
In-Reply-To: <alpine.LRH.2.00.1103260047590.26023@bmsred.bmsi.com>

On 03/25/2011 11:52 PM, Stuart D. Gathman wrote:
> On Fri, 25 Mar 2011, Ron Johnson wrote:
>
>> On 03/25/2011 11:24 PM, Stuart D. Gathman wrote:
>> [snip]
>>>
>>> 2) make sure important LVs do not span multiple PVs (except for LVM
>>> mirroring) - you could be unhappy in the event of a system crash.
>>>
>>
>> But isn't "volumes larger than physical devices" (one of) the raison
>> d'etre of LVM?
>
> Yes, but a power failure can then mess up the ordering of write completions
> distributed between 2 or more PVs, which could defeat the assumptions made
> by your file system journaling.
>

File a bug...  But against what?  LVM?  The FS?  The block layer?

> and
>
> No, YMMV, but I generally have a number of smaller LVs (for virtual
> machines)
> and it is nice to have a larger pool of PVs from which they are allocated.
>

I guess I'm just a DP Dinosaur who thinks that if a machine is beefy
enough to run a bunch of services then those services should run 
directly on the machine.  (Obviously I don't work for a web hosting 
company...)

-- 
"Neither the wisest constitution nor the wisest laws will secure
the liberty and happiness of a people whose manners are universally
corrupt."
Samuel Adams, essay in The Public Advertiser, 1749

  reply	other threads:[~2011-03-26  5:25 UTC|newest]

Thread overview: 17+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-03-26  4:24 [linux-lvm] Powerfailure and snapshot consistency Stuart D. Gathman
2011-03-26  4:42 ` Ron Johnson
2011-03-26  4:52   ` Stuart D. Gathman
2011-03-26  5:25     ` Ron Johnson [this message]
2011-03-26  5:53       ` hansbkk
2011-03-26 16:07       ` Stuart D. Gathman
2011-03-26 20:30         ` Mike Snitzer
2011-03-27 21:55           ` Stuart D. Gathman
2011-03-28 17:20             ` Phillip Susi
2011-03-28 17:24               ` Stuart D. Gathman
2011-03-28 17:37                 ` Phillip Susi
2011-03-28 21:26                   ` Stuart D. Gathman
2011-03-28 18:34                 ` Mike Snitzer
2011-03-28 17:26         ` Les Mikesell
2011-03-28 17:54           ` Stuart D. Gathman
2011-03-28 19:43             ` Ron Johnson
2011-03-26  7:49 ` Ray Morris

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