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Posted to user@cassandra.apache.org by Jian Fang <ji...@gmail.com> on 2011/07/28 16:47:02 UTC
Cassandra 0.6.8 snapshot problem?
Hi,
We have an old production Cassandra 0.6.8 instance without replica, i.e.,
the replication factor is 1. Recently, we noticed that
the snapshot data we took from this instance are inconsistent with the
running instance data. For example, we took snapshot
in early July 2011. From the running instance, we got a record that was
created in March 2011, but on the snapshot copy, the
record with the same key was different and was created in January 2011.
Yesterday, we created another snapshot and reproduced
the problem. I just like to know if this is a known issue for Cassandra 0.6.
We are going to migrate to Cassandra 0.8, but we need to make sure this will
not be a problem in 0.8.
Thanks in advance,
John
Re: Cassandra 0.6.8 snapshot problem?
Posted by Jian Fang <ji...@gmail.com>.
We simply copy the snapshot data to another cluster to replace its data
directory. This cluster does not have any incoming traffic.
I haven't compared the md5 sum yet. Will try that.
Thanks,
John
On Thu, Jul 28, 2011 at 10:27 PM, Zhu Han <sc...@gmail.com> wrote:
>
>
> On Thu, Jul 28, 2011 at 10:47 PM, Jian Fang <jian.fang.subscribe@gmail.com
> > wrote:
>
>> Hi,
>>
>> We have an old production Cassandra 0.6.8 instance without replica, i.e.,
>> the replication factor is 1. Recently, we noticed that
>> the snapshot data we took from this instance are inconsistent with the
>> running instance data. For example, we took snapshot
>> in early July 2011. From the running instance, we got a record that was
>> created in March 2011, but on the snapshot copy, the
>> record with the same key was different and was created in January 2011.
>> Yesterday, we created another snapshot and reproduced
>> the problem. I just like to know if this is a known issue for Cassandra
>> 0.6.
>>
>
> Do you see any difference between the sstables of running instance and the
> snapshot? You can use md5sum to compare them.
>
> How do you load the snapshot to another cluster?
>
>>
>> We are going to migrate to Cassandra 0.8, but we need to make sure this
>> will not be a problem in 0.8.
>>
>> Thanks in advance,
>>
>> John
>>
>>
>
Re: Cassandra 0.6.8 snapshot problem?
Posted by Zhu Han <sc...@gmail.com>.
On Thu, Jul 28, 2011 at 10:47 PM, Jian Fang
<ji...@gmail.com>wrote:
> Hi,
>
> We have an old production Cassandra 0.6.8 instance without replica, i.e.,
> the replication factor is 1. Recently, we noticed that
> the snapshot data we took from this instance are inconsistent with the
> running instance data. For example, we took snapshot
> in early July 2011. From the running instance, we got a record that was
> created in March 2011, but on the snapshot copy, the
> record with the same key was different and was created in January 2011.
> Yesterday, we created another snapshot and reproduced
> the problem. I just like to know if this is a known issue for Cassandra
> 0.6.
>
Do you see any difference between the sstables of running instance and the
snapshot? You can use md5sum to compare them.
How do you load the snapshot to another cluster?
>
> We are going to migrate to Cassandra 0.8, but we need to make sure this
> will not be a problem in 0.8.
>
> Thanks in advance,
>
> John
>
>
Re: Cassandra 0.6.8 snapshot problem?
Posted by Jonathan Ellis <jb...@gmail.com>.
0.6.13 flushes first, and I don't remember changing that earlier in
0.6, but you'd have to check ColumnFamilyStore.snapshot in 0.6.8 to be
100% sure
On Tue, Aug 2, 2011 at 4:08 PM, Jeremiah Jordan
<je...@morningstar.com> wrote:
> Does snapshot in 0.6 cause a flush to happen first? If not there could
> be data in the database that won't be in the snapshot. Though that
> seems like a long time for data to be sitting in the commit log and not
> make it to the sstables.
>
> On Thu, 2011-07-28 at 17:30 -0500, Jonathan Ellis wrote:
>> Doesn't ring a bell. But I'd say if you upgrade and it's still a
>> problem, then (a) you're not _worse_ off than you are now, and (b)
>> it's a lot more likely to get fixed in modern version.
>>
>> On Thu, Jul 28, 2011 at 9:47 AM, Jian Fang
>> <ji...@gmail.com> wrote:
>> > Hi,
>> >
>> > We have an old production Cassandra 0.6.8 instance without replica, i.e.,
>> > the replication factor is 1. Recently, we noticed that
>> > the snapshot data we took from this instance are inconsistent with the
>> > running instance data. For example, we took snapshot
>> > in early July 2011. From the running instance, we got a record that was
>> > created in March 2011, but on the snapshot copy, the
>> > record with the same key was different and was created in January 2011.
>> > Yesterday, we created another snapshot and reproduced
>> > the problem. I just like to know if this is a known issue for Cassandra 0.6.
>> >
>> > We are going to migrate to Cassandra 0.8, but we need to make sure this will
>> > not be a problem in 0.8.
>> >
>> > Thanks in advance,
>> >
>> > John
>> >
>> >
>>
>>
>>
>
>
--
Jonathan Ellis
Project Chair, Apache Cassandra
co-founder of DataStax, the source for professional Cassandra support
http://www.datastax.com
Re: Cassandra 0.6.8 snapshot problem?
Posted by Jeremiah Jordan <je...@morningstar.com>.
Does snapshot in 0.6 cause a flush to happen first? If not there could
be data in the database that won't be in the snapshot. Though that
seems like a long time for data to be sitting in the commit log and not
make it to the sstables.
On Thu, 2011-07-28 at 17:30 -0500, Jonathan Ellis wrote:
> Doesn't ring a bell. But I'd say if you upgrade and it's still a
> problem, then (a) you're not _worse_ off than you are now, and (b)
> it's a lot more likely to get fixed in modern version.
>
> On Thu, Jul 28, 2011 at 9:47 AM, Jian Fang
> <ji...@gmail.com> wrote:
> > Hi,
> >
> > We have an old production Cassandra 0.6.8 instance without replica, i.e.,
> > the replication factor is 1. Recently, we noticed that
> > the snapshot data we took from this instance are inconsistent with the
> > running instance data. For example, we took snapshot
> > in early July 2011. From the running instance, we got a record that was
> > created in March 2011, but on the snapshot copy, the
> > record with the same key was different and was created in January 2011.
> > Yesterday, we created another snapshot and reproduced
> > the problem. I just like to know if this is a known issue for Cassandra 0.6.
> >
> > We are going to migrate to Cassandra 0.8, but we need to make sure this will
> > not be a problem in 0.8.
> >
> > Thanks in advance,
> >
> > John
> >
> >
>
>
>
Re: Cassandra 0.6.8 snapshot problem?
Posted by Jonathan Ellis <jb...@gmail.com>.
Doesn't ring a bell. But I'd say if you upgrade and it's still a
problem, then (a) you're not _worse_ off than you are now, and (b)
it's a lot more likely to get fixed in modern version.
On Thu, Jul 28, 2011 at 9:47 AM, Jian Fang
<ji...@gmail.com> wrote:
> Hi,
>
> We have an old production Cassandra 0.6.8 instance without replica, i.e.,
> the replication factor is 1. Recently, we noticed that
> the snapshot data we took from this instance are inconsistent with the
> running instance data. For example, we took snapshot
> in early July 2011. From the running instance, we got a record that was
> created in March 2011, but on the snapshot copy, the
> record with the same key was different and was created in January 2011.
> Yesterday, we created another snapshot and reproduced
> the problem. I just like to know if this is a known issue for Cassandra 0.6.
>
> We are going to migrate to Cassandra 0.8, but we need to make sure this will
> not be a problem in 0.8.
>
> Thanks in advance,
>
> John
>
>
--
Jonathan Ellis
Project Chair, Apache Cassandra
co-founder of DataStax, the source for professional Cassandra support
http://www.datastax.com