you need 2 more things: - restart hdfs - make sure the hadoop jar from your install replaces the one we ship with
On Mon, Sep 20, 2010 at 8:22 PM, Jack Levin <[email protected]> wrote: > So, I switched to 0.89, and we already had CDH3 > (hadoop-0.20-datanode-0.20.2+320-3.noarch), even though I added > <name>dfs.support.append</name> as true to both hdfs-site.xml and > hbase-site.xml, the master still reports this: > > You are currently running the HMaster without HDFS append support > enabled. This may result in data loss. Please see the HBase wiki for > details. > Master Attributes > Attribute Name Value Description > HBase Version 0.89.20100726, r979826 HBase version and svn revision > HBase Compiled Sat Jul 31 02:01:58 PDT 2010, stack When HBase version > was compiled and by whom > Hadoop Version 0.20.2, r911707 Hadoop version and svn revision > Hadoop Compiled Fri Feb 19 08:07:34 UTC 2010, chrisdo When Hadoop > version was compiled and by whom > HBase Root Directory hdfs://namenode-rd.imageshack.us:9000/hbase > Location > of HBase home directory > > Any ideas whats wrong? > > -Jack > > > On Mon, Sep 20, 2010 at 5:47 PM, Ryan Rawson <[email protected]> wrote: >> Hey, >> >> There is actually only 1 active branch of hbase, that being the 0.89 >> release, which is based on 'trunk'. We have snapshotted a series of >> 0.89 "developer releases" in hopes that people would try them our and >> start thinking about the next major version. One of these is what SU >> is running prod on. >> >> At this point tracking 0.89 and which ones are the 'best' peach sets >> to run is a bit of a contact sport, but if you are serious about not >> losing data it is worthwhile. SU is based on the most recent DR with >> a few minor patches of our own concoction brought in. If current >> works, but some Master ops are slow, and there are a few patches on >> top of that. I'll poke about and see if its possible to publish to a >> github branch or something. >> >> -ryan >> >> On Mon, Sep 20, 2010 at 5:16 PM, Jack Levin <[email protected]> wrote: >>> Sounds, good, only reason I ask is because of this: >>> >>> There are currently two active branches of HBase: >>> >>> * 0.20 - the current stable release series, being maintained with >>> patches for bug fixes only. This release series does not support HDFS >>> durability - edits may be lost in the case of node failure. >>> * 0.89 - a development release series with active feature and >>> stability development, not currently recommended for production use. >>> This release does support HDFS durability - cases in which edits are >>> lost are considered serious bugs. >>>>>>>>> >>> >>> Are we talking about data loss in case of datanode going down while >>> being written to, or RegionServer going down? >>> >>> -jack >>> >>> >>> On Mon, Sep 20, 2010 at 4:09 PM, Ryan Rawson <[email protected]> wrote: >>>> We run 0.89 in production @ Stumbleupon. We also employ 3 committers... >>>> >>>> As for safety, you have no choice but to run 0.89. If you run a 0.20 >>>> release you will lose data. you must be on 0.89 and >>>> CDH3/append-branch to achieve data durability, and there really is no >>>> argument around it. If you are doing your tests with 0.20.6 now, I'd >>>> stop and rebase those tests onto the latest DR announced on the list. >>>> >>>> -ryan >>>> >>>> On Mon, Sep 20, 2010 at 3:17 PM, Jack Levin <[email protected]> wrote: >>>>> Hi Stack, see inline: >>>>> >>>>> On Mon, Sep 20, 2010 at 2:42 PM, Stack <[email protected]> wrote: >>>>>> Hey Jack: >>>>>> >>>>>> Thanks for writing. >>>>>> >>>>>> See below for some comments. >>>>>> >>>>>> On Mon, Sep 20, 2010 at 11:00 AM, Jack Levin <[email protected]> wrote: >>>>>>> >>>>>>> Image-Shack gets close to two million image uploads per day, which are >>>>>>> usually stored on regular servers (we have about 700), as regular >>>>>>> files, and each server has its own host name, such as (img55). I've >>>>>>> been researching on how to improve our backend design in terms of data >>>>>>> safety and stumped onto the Hbase project. >>>>>>> >>>>>> >>>>>> Any other requirements other than data safety? (latency, etc). >>>>> >>>>> Latency is the second requirement. We have some services that are >>>>> very short tail, and can produce 95% cache hit rate, so I assume this >>>>> would really put cache into good use. Some other services however, >>>>> have about 25% cache hit ratio, in which case the latency should be >>>>> 'adequate', e.g. if its slightly worse than getting data off raw disk, >>>>> then its good enough. Safely is supremely important, then its >>>>> availability, then speed. >>>>> >>>>> >>>>> >>>>>>> Now, I think hbase is he most beautiful thing that happen to >>>>>>> distributed DB world :). The idea is to store image files (about >>>>>>> 400Kb on average into HBASE). >>>>>> >>>>>> >>>>>> I'd guess some images are much bigger than this. Do you ever limit >>>>>> the size of images folks can upload to your service? >>>>>> >>>>>> >>>>>> The setup will include the following >>>>>>> configuration: >>>>>>> >>>>>>> 50 servers total (2 datacenters), with 8 GB RAM, dual core cpu, 6 x >>>>>>> 2TB disks each. >>>>>>> 3 to 5 Zookeepers >>>>>>> 2 Masters (in a datacenter each) >>>>>>> 10 to 20 Stargate REST instances (one per server, hash loadbalanced) >>>>>> >>>>>> Whats your frontend? Why REST? It might be more efficient if you >>>>>> could run with thrift given REST base64s its payload IIRC (check the >>>>>> src yourself). >>>>> >>>>> For insertion we use Haproxy, and balance curl PUTs across multiple REST >>>>> APIs. >>>>> For reading, its a nginx proxy that does Content-type modification >>>>> from image/jpeg to octet-stream, and vice versa, >>>>> it then hits Haproxy again, which hits balanced REST. >>>>> Why REST, it was the simplest thing to run, given that its supports >>>>> HTTP, potentially we could rewrite something for thrift, as long as we >>>>> can use http still to send and receive data (anyone wrote anything >>>>> like that say in python, C or java?) >>>>> >>>>>> >>>>>>> 40 to 50 RegionServers (will probably keep masters separate on >>>>>>> dedicated boxes). >>>>>>> 2 Namenode servers (one backup, highly available, will do fsimage and >>>>>>> edits snapshots also) >>>>>>> >>>>>>> So far I got about 13 servers running, and doing about 20 insertions / >>>>>>> second (file size ranging from few KB to 2-3MB, ave. 400KB). via >>>>>>> Stargate API. Our frontend servers receive files, and I just >>>>>>> fork-insert them into stargate via http (curl). >>>>>>> The inserts are humming along nicely, without any noticeable load on >>>>>>> regionservers, so far inserted about 2 TB worth of images. >>>>>>> I have adjusted the region file size to be 512MB, and table block size >>>>>>> to about 400KB , trying to match average access block to limit HDFS >>>>>>> trips. >>>>>> >>>>>> As Todd suggests, I'd go up from 512MB... 1G at least. You'll >>>>>> probably want to up your flush size from 64MB to 128MB or maybe 192MB. >>>>> >>>>> Yep, i will adjust to 1G. I thought flush was controlled by a >>>>> function of memstore HEAP, something like 40%? Or are you talking >>>>> about HDFS block size? >>>>> >>>>>> So far the read performance was more than adequate, and of >>>>>>> course write performance is nowhere near capacity. >>>>>>> So right now, all newly uploaded images go to HBASE. But we do plan >>>>>>> to insert about 170 Million images (about 100 days worth), which is >>>>>>> only about 64 TB, or 10% of planned cluster size of 600TB. >>>>>>> The end goal is to have a storage system that creates data safety, >>>>>>> e.g. system may go down but data can not be lost. Our Front-End >>>>>>> servers will continue to serve images from their own file system (we >>>>>>> are serving about 16 Gbits at peak), however should we need to bring >>>>>>> any of those down for maintenance, we will redirect all traffic to >>>>>>> Hbase (should be no more than few hundred Mbps), while the front end >>>>>>> server is repaired (for example having its disk replaced), after the >>>>>>> repairs, we quickly repopulate it with missing files, while serving >>>>>>> the missing remaining off Hbase. >>>>>>> All in all should be very interesting project, and I am hoping not to >>>>>>> run into any snags, however, should that happens, I am pleased to know >>>>>>> that such a great and vibrant tech group exists that supports and uses >>>>>>> HBASE :). >>>>>>> >>>>>> >>>>>> We're definetly interested in how your project progresses. If you are >>>>>> ever up in the city, you should drop by for a chat. >>>>> >>>>> Cool. I'd like that. >>>>> >>>>>> St.Ack >>>>>> >>>>>> P.S. I'm also w/ Todd that you should move to 0.89 and blooms. >>>>>> P.P.S I updated the wiki on stargate REST: >>>>>> http://wiki.apache.org/hadoop/Hbase/Stargate >>>>> >>>>> Cool, I assume if we move to that it won't kill existing meta tables, >>>>> and data? e.g. cross compatible? >>>>> Is 0.89 ready for production environment? >>>>> >>>>> -Jack >>>>> >>>> >>> >> >
