Hello,
I am still in my first steps with HBase, I was used to use Cassandra a while
ago.
For several years, I was used to think trying to store data in Cassandra
ordered among nodes was something evil, as it's OrderedPartitioner is something
not supported and not recommended in production.
Hi Team,
I am trying to use hbase 0.98 distributed mode with zk 3.4.6 hadoop ha
2.6.(JDK 1.8)
I am having following issue and little help in google pages also
I tried to start zk first after clearing zk data dir and tried to start master
first and rs later and no luck
I used mycluster/hbase in
If I have an application that writes to a HBase cluster, can I count that the
cluster will always available to receive writes?
I might not be able to read if a region server which handles a range of keys is
down, but will I be able to keep writing to other nodes, so everything get in
sync when
Thanks Serega, it helps me to understand the differences.
From: user@hbase.apache.org
Subject: Re: write availability
If I have an application that writes to a HBase cluster, can I count that
the cluster will always available to receive writes?
No, it's CP, not AP system.
so everything get in
I don’t know if I would say that…
I read Marcelo’s question of “if the cluster is up, even though a RS may be
down, can I still insert records in to HBase?”
So if the cluster is up, then you can insert records in to HBase even though
you lost a RS that was handing a specific region.
But
If I have an application that writes to a HBase cluster, can I count that
the cluster will always available to receive writes?
No, it's CP, not AP system.
so everything get in sync when the other nodes get up again
There is no hinted backoff, It's not Cassandra.
2015-04-07 14:48 GMT+02:00
Hi,
This is my hbase-site.xml:
configuration propertynamehbase.master/name
valuehdfs://cluster1:6/value /property property
namehbase.rootdir/namevaluehdfs://mycluster/hbase/value
/property property
Team,
The port the HBase Master should bind to 6
Thanks,Sridhar From: serega.shey...@gmail.com
Date: Tue, 7 Apr 2015 16:40:54 +0200
Subject: Re: Hbase 0.98 Distributed Mode with hadoop 2.6 HA:Issues of Hbase
To: user@hbase.apache.org
CC: bus...@cloudera.com
property
property
namehbase.master/name
valuehdfs://cluster1:6/value
/property
what is it?
2015-04-07 16:34 GMT+02:00 sridhararao mutluri drm...@hotmail.com:
Hi,
This is my hbase-site.xml:
configuration propertynamehbase.master/name
valuehdfs://cluster1:6/value
bq. propertynamehbase.rootdir/name
valuehdfs://mycluster/hbase/value /property property
Looks like there is a property missing at the end of the line.
You showed snippet from shell output. Have you checked master log ?
Cheers
On Tue, Apr 7, 2015 at 5:16 AM, sridhararao
Wellington,
I might be misinterpreting this:
http://stackoverflow.com/questions/13741946/role-of-datanode-regionserver-in-hbase-hadoop-integration
But aren't HBase region servers and HDFS datanodes always in the same server?
With a replication factor of 3, what happens if all 3 datanodes
Sridhar,
What do you see in the HBase Master logs? The exception you are getting
from the HBase Master is just a side effect and not the real cause? Is it
possible for you to upload the HBase Master logs to a site like pastebin.com
or gist.github.com so we can look at?
cheers,
esteban.
--
Marcelo, if you are comparing with Cassandra:
1. don't think about data replication/redundancy. It's out of HBase scope.
C* thinks about it, HBase doesn't HBase uses HDFS. So assume you never-ever
can lost the data. Assume, that HDFS configured properly.
2. HBase doesn't think in terms of
But aren't HBase region servers and HDFS datanodes always in the same
server?
It's good point, but it's not mandatory.
With a replication factor of 3, what happens if all 3 datanodes hosting
that information go down and one of them come back, but with the disk
intact?
Should be OK. you have 3
Hello Marcelo,
HBase has strong durability guarantees to avoid data loss. When a write
arrives to a RegionServer data will be persisted into a Write-Ahead-Log (on
HDFS) and temporarily in the RegionServer memory until the data from this
memory store is flushed (also to HDFS).
For the point of
So if a RS goes down, it's assumed you lost the data on it, right?
HBase has replications on HDFS, so if a RS goes down it doesn't mean I lost all
the data, as I could have the replicas yet... But what happens if all RS
hosting a specific region goes down?
What if one RS from this one comes
Hi
I have a row with around 100.000 qualifiers with mostly small values around
1-5KB and maybe 5 largers ones around 1-5 MB. A coprocessor do random
access of 1-10 qualifiers per row.
I would like to understand how HBase loads the data into memory. Will the
entire row be loaded or only the
Hi Marcelo,
As you well know, HBase partitions your data set into row key ranges --
regions. Each region is assigned to a single region server, which is the
sole responsible host** for the availability of that region. When a region
is offline, for whatever reason, it is not available for
When a RS goes down, the Master will try to assign the regions on the remaining
RSes. When the RS comes back, after a while, the Master balancer process will
re-distribute regions between RS, so the given RS will be hosting regions, but
not necessarily the one it used to host before it went
So if the cluster is up, then you can insert records in to HBase even though
you lost a RS that was handing a specific region.
What happens when the RS goes down? Writes to that region will be written to
another region server? Another RS assumes the region range while the RS is
down?
What
Sorry, there is something I asked wrongly because I was understanding it
wrongly.
1 region server correspond to 1 namenode and 1 write to 1 name node will
replicate to 3 datanodes...
No, but this may just be a terminology problem.
The NameNode isn't an HBase daemon, it's HDFS.
HDFS writers,
how HBase loads the data into memory.
If you init Get and specify columns with addColumn, it is likely that only
data for these columns is read and loaded in memory.
Rowkey is best kept short. So are column qualifiers.
Sorry, there is something I asked wrongly because I was understanding it
wrongly.
1 region server correspond to 1 namenode and 1 write to 1 name node will
replicate to 3 datanodes...
So to simplify the second question, what happens to the HBase cluster when 1
region server is down?
-Marcelo
--
Cloudera, Inc.
On Tue, Apr 7, 2015 at 10:36 AM, Marcelo Valle (BLOOMBERG/ LONDON)
mvallemil...@bloomberg.net wrote:
Sorry, there is something I asked wrongly because I was understanding it
wrongly.
1 region server correspond to 1 namenode and 1 write to 1 name node will
replicate to 3
Esteban,
If I understood correctly what you said:
For the failure mode you mention if all DNs go down (not the NN) clients
will be blocked waiting for the acknowledge of a write to the DNs and after
few retries the RS will consider there was a failure writing to the WAL, the
RS will
Hello Marcelo,
On Tue, Apr 7, 2015 at 10:16 AM, Marcelo Valle (BLOOMBERG/ LONDON)
mvallemil...@bloomberg.net wrote:
Esteban,
If I understood correctly what you said:
For the failure mode you mention if all DNs go down (not the NN)
clients will be blocked waiting for the acknowledge of a
Sorry I should have explained my use case a bit more.
Yes, it's a pretty big row and it's close to worst case. Normally there
would be fewer qualifiers and the largest qualifiers would be smaller.
The reason why these rows gets big is because they stores aggregated data
in indexed compressed
Sorry, but your initial problem statement doesn’t seem to parse …
Are you saying that you a single row with approximately 100,000 elements where
each element is roughly 1-5KB in size and in addition there are ~5 elements
which will be between one and five MB in size?
And you then mention a
Those rows are written out into HBase blocks on cell boundaries. Your
column family has a BLOCK_SIZE attribute, which you may or may have no
overridden the default of 64k. Cells are written into a block until is it
= the target block size. So your single 500mb row will be broken down into
hi, folks,
I have a question about region assignment and like to clarify some through.
Let's say I have a table with rowkey as row0 ~ row3 on a 4 node
hbase cluster, is there a way to keep data partitioned by range on each
node? for example:
node1: =row1
node2: row10001~row2
Hi Esteban,
I pasted logs in github.com:
Thanks,Sridhar
From: este...@cloudera.com
Date: Tue, 7 Apr 2015 08:44:55 -0700
Subject: Re: Hbase 0.98 Distributed Mode with hadoop 2.6 HA:Issues of Hbase
To: user@hbase.apache.org
Sridhar,
What do you see in the HBase Master logs?
Heya folks,
We're down to a week remaining before my proposed branch date. A couple
big-ticket items have made it in since my last mail (HBASE-12972,
HBASE-12975, HBASE-11598, HBASE-13170). However, we still have about 70
unresolved issues marked for this release, including 3 blockers
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