And will you be so kind as to share the link with this email distro please?
On 1/16/19, 11:41 AM, "Keith Turner" <[email protected]> wrote: Maxim, This is very interesting. Would you be interested in writing an Accumulo blog post about your experience? If you are interested I can help. Keith On Tue, Jan 15, 2019 at 10:03 AM Maxim Kolchin <[email protected]> wrote: > > Hi, > > I just wanted to leave intermediate feedback on the topic. > > So far, Accumulo works pretty well on top of Google Storage. The aforementioned issue still exists, but it doesn't break anything. However, I can't give you any useful performance numbers at the moment. > > The cluster: > > - master (with zookeeper) (n1-standard-1) + 2 tservers (n1-standard-4) > - 32+ billlion entries > - 5 tables (excluding system tables) > > Some averaged numbers from two use cases: > > - batch write into pre-splitted tables with 40 client machines + 4 tservers (n1-standard-4) - max speed 1.5M entries/sec. > - sequential read with 2 client iterators (1 - filters by key, 2- filters by timestamp), with 5 client machines + 2 tservers (n1-standard-4 ) and less than 60k entries returned - max speed 1M+ entries/sec. > > Maxim > > On Mon, Jun 25, 2018 at 12:57 AM Christopher <[email protected]> wrote: >> >> Ah, ok. One of the comments on the issue led me to believe that it was the same issue as the missing custom log closer. >> >> On Sat, Jun 23, 2018, 01:10 Stephen Meyles <[email protected]> wrote: >>> >>> > I'm not convinced this is a write pattern issue, though. I commented on.. >>> >>> The note there suggests the need for a LogCloser implementation; in my (ADLS) case I've written one and have it configured - the exception I'm seeing involves failures during writes, not during recovery (though it then leads to a need for recovery). >>> >>> S. >>> >>> On Fri, Jun 22, 2018 at 4:33 PM, Christopher <[email protected]> wrote: >>>> >>>> Unfortunately, that feature wasn't added until 2.0, which hasn't yet been released, but I'm hoping it will be later this year. >>>> >>>> However, I'm not convinced this is a write pattern issue, though. I commented on https://urldefense.proofpoint.com/v2/url?u=https-3A__github.com_GoogleCloudPlatform_bigdata-2Dinterop_issues_103-23issuecomment-2D399608543&d=DwIFaQ&c=LFYZ-o9_HUMeMTSQicvjIg&r=tVgyCjxnNiJ0cjUcKRQFKA&m=Dh1LN-vxvgWAW9nDdnINj7ultMEGn6AjW4IGFLed30w&s=RrpeKiRhbHsbTPStmmN3yjoOdB8n7TXkrQdYjvqOb54&e= >>>> >>>> On Fri, Jun 22, 2018 at 1:50 PM Stephen Meyles <[email protected]> wrote: >>>>> >>>>> Knowing that HBase has been run successfully on ADLS, went looking there (as they have the same WAL write pattern). This is informative: >>>>> >>>>> https://urldefense.proofpoint.com/v2/url?u=https-3A__www.cloudera.com_documentation_enterprise_5-2D12-2Dx_topics_admin-5Fusing-5Fadls-5Fstorage-5Fwith-5Fhbase.html&d=DwIFaQ&c=LFYZ-o9_HUMeMTSQicvjIg&r=tVgyCjxnNiJ0cjUcKRQFKA&m=Dh1LN-vxvgWAW9nDdnINj7ultMEGn6AjW4IGFLed30w&s=A3SBTtG6DoNjpwDwd90-4Cnmi2WwE5TRxbAjBmzwaRI&e= >>>>> >>>>> which suggests a need to split the WALs off on HDFS proper versus ADLS (or presumably GCS) barring changes in the underlying semantics of each. AFAICT you can't currently configure Accumulo to send WAL logs to a separate cluster - is this correct? >>>>> >>>>> S. >>>>> >>>>> >>>>> On Fri, Jun 22, 2018 at 9:07 AM, Stephen Meyles <[email protected]> wrote: >>>>>> >>>>>> > Did you try to adjust any Accumulo properties to do bigger writes less frequently or something like that? >>>>>> >>>>>> We're using BatchWriters and sending reasonable larges batches of Mutations. Given the stack traces in both our cases are related to WAL writes it seems like batch size would be the only tweak available here (though, without reading the code carefully it's not even clear to me that is impactful) but if there others have suggestions I'd be happy to try. >>>>>> >>>>>> Given we have this working well and stable in other clusters atop traditional HDFS I'm currently pursuing this further with the MS to understand the variance to ADLS. Depending what emerges from that I may circle back with more details and a bug report and start digging in more deeply to the relevant code in Accumulo. >>>>>> >>>>>> S. >>>>>> >>>>>> >>>>>> On Fri, Jun 22, 2018 at 6:09 AM, Maxim Kolchin <[email protected]> wrote: >>>>>>> >>>>>>> > If somebody is interested in using Accumulo on GCS, I'd like to encourage them to submit any bugs they encounter, and any patches (if they are able) which resolve those bugs. >>>>>>> >>>>>>> I'd like to contribute a fix, but I don't know where to start. We tried to get any help from the Google Support about [1] over email, but they just say that the GCS doesn't support such write pattern. In the end, we can only guess how to adjust the Accumulo behaviour to minimise broken connections to the GCS. >>>>>>> >>>>>>> BTW although we observe this exception, the tablet server doesn't fail, so it means that after some retries it is able to write WALs to GCS. >>>>>>> >>>>>>> @Stephen, >>>>>>> >>>>>>> > as discussions with MS engineers have suggested, similar to the GCS thread, that small writes at high volume are, at best, suboptimal for ADLS. >>>>>>> >>>>>>> Did you try to adjust any Accumulo properties to do bigger writes less frequently or something like that? >>>>>>> >>>>>>> [1]: https://urldefense.proofpoint.com/v2/url?u=https-3A__github.com_GoogleCloudPlatform_bigdata-2Dinterop_issues_103&d=DwIFaQ&c=LFYZ-o9_HUMeMTSQicvjIg&r=tVgyCjxnNiJ0cjUcKRQFKA&m=Dh1LN-vxvgWAW9nDdnINj7ultMEGn6AjW4IGFLed30w&s=2yPpLqw3V32UFtuTULJ4GIgrpBpvRT6k3sdvxxE7gys&e= >>>>>>> >>>>>>> Maxim >>>>>>> >>>>>>> On Thu, Jun 21, 2018 at 7:17 AM Stephen Meyles <[email protected]> wrote: >>>>>>>> >>>>>>>> I think we're seeing something similar but in our case we're trying to run Accumulo atop ADLS. When we generate sufficient write load we start to see stack traces like the following: >>>>>>>> >>>>>>>> [log.DfsLogger] ERROR: Failed to write log entries >>>>>>>> java.io.IOException: attempting to write to a closed stream; >>>>>>>> at com.microsoft.azure.datalake.store.ADLFileOutputStream.write(ADLFileOutputStream.java:88) >>>>>>>> at com.microsoft.azure.datalake.store.ADLFileOutputStream.write(ADLFileOutputStream.java:77) >>>>>>>> at org.apache.hadoop.fs.adl.AdlFsOutputStream.write(AdlFsOutputStream.java:57) >>>>>>>> at org.apache.hadoop.fs.FSDataOutputStream$PositionCache.write(FSDataOutputStream.java:48) >>>>>>>> at java.io.DataOutputStream.write(DataOutputStream.java:88) >>>>>>>> at java.io.DataOutputStream.writeByte(DataOutputStream.java:153) >>>>>>>> at org.apache.accumulo.tserver.logger.LogFileKey.write(LogFileKey.java:87) >>>>>>>> at org.apache.accumulo.tserver.log.DfsLogger.write(DfsLogger.java:537) >>>>>>>> >>>>>>>> We have developed a rudimentary LogCloser implementation that allows us to recover from this but overall performance is significantly impacted by this. >>>>>>>> >>>>>>>> > As for the WAL closing issue on GCS, I recall a previous thread about that >>>>>>>> >>>>>>>> I searched more for this but wasn't able to find anything, nor similar re: ADL. I am also curious about the earlier question: >>>>>>>> >>>>>>>> >> Does Accumulo have a specific write pattern [to WALs], so that file system may not support it? >>>>>>>> >>>>>>>> as discussions with MS engineers have suggested, similar to the GCS thread, that small writes at high volume are, at best, suboptimal for ADLS. >>>>>>>> >>>>>>>> Regards >>>>>>>> >>>>>>>> Stephen >>>>>>>> >>>>>>>> >>>>>>>> On Wed, Jun 20, 2018 at 11:20 AM, Christopher <[email protected]> wrote: >>>>>>>>> >>>>>>>>> For what it's worth, this is an Apache project, not a Sqrrl project. Amazon is free to contribute to Accumulo to improve its support of their platform, just as anybody is free to do. Amazon may start contributing more as a result of their acquisition... or they may not. There is no reason to expect that their acquisition will have any impact whatsoever on the platforms Accumulo supports, because Accumulo is not, and has not ever been, a Sqrrl project (although some Sqrrl employees have contributed), and thus will not become an Amazon project. It has been, and will remain, a vendor-neutral Apache project. Regardless, we welcome contributions from anybody which would improve Accumulo's support of any additional platform alternatives to HDFS, whether it be GCS, S3, or something else. >>>>>>>>> >>>>>>>>> As for the WAL closing issue on GCS, I recall a previous thread about that... I think a simple patch might be possible to solve that issue, but to date, nobody has contributed a fix. If somebody is interested in using Accumulo on GCS, I'd like to encourage them to submit any bugs they encounter, and any patches (if they are able) which resolve those bugs. If they need help submitting a fix, please ask on the dev@ list. >>>>>>>>> >>>>>>>>> >>>>>>>>> >>>>>>>>> On Wed, Jun 20, 2018 at 8:21 AM Geoffry Roberts <[email protected]> wrote: >>>>>>>>>> >>>>>>>>>> Maxim, >>>>>>>>>> >>>>>>>>>> Interesting that you were able to run A on GCS. I never thought of that--good to know. >>>>>>>>>> >>>>>>>>>> Since I am now an AWS guy (at least or the time being), in light of the fact that Amazon purchased Sqrrl, I am interested to see what develops. >>>>>>>>>> >>>>>>>>>> >>>>>>>>>> On Wed, Jun 20, 2018 at 5:15 AM, Maxim Kolchin <[email protected]> wrote: >>>>>>>>>>> >>>>>>>>>>> Hi Geoffry, >>>>>>>>>>> >>>>>>>>>>> Thank you for the feedback! >>>>>>>>>>> >>>>>>>>>>> Thanks to [1, 2], I was able to run Accumulo cluster on Google VMs and with GCS instead of HDFS. And I used Google Dataproc to run Hadoop jobs on Accumulo. Almost everything was good until I've not faced some connection issues with GCS. Quite often, the connection to GCS breaks on writing or closing WALs. >>>>>>>>>>> >>>>>>>>>>> To all, >>>>>>>>>>> >>>>>>>>>>> Does Accumulo have a specific write pattern, so that file system may not support it? Are there Accumulo properties which I can play with to adjust the write pattern? >>>>>>>>>>> >>>>>>>>>>> [1]: https://urldefense.proofpoint.com/v2/url?u=https-3A__github.com_cybermaggedon_accumulo-2Dgs&d=DwIFaQ&c=LFYZ-o9_HUMeMTSQicvjIg&r=tVgyCjxnNiJ0cjUcKRQFKA&m=Dh1LN-vxvgWAW9nDdnINj7ultMEGn6AjW4IGFLed30w&s=K3sM4QEXbilBZ-bDW-ld4a7WxgTkHn5Ms4P_BaIvfmo&e= >>>>>>>>>>> [2]: https://urldefense.proofpoint.com/v2/url?u=https-3A__github.com_cybermaggedon_accumulo-2Ddocker&d=DwIFaQ&c=LFYZ-o9_HUMeMTSQicvjIg&r=tVgyCjxnNiJ0cjUcKRQFKA&m=Dh1LN-vxvgWAW9nDdnINj7ultMEGn6AjW4IGFLed30w&s=9jRnuv65SKmppVkDI1tKNRKcOZJDfXFiSRS5Pcxt2fU&e= >>>>>>>>>>> >>>>>>>>>>> Thank you! >>>>>>>>>>> Maxim >>>>>>>>>>> >>>>>>>>>>> On Tue, Jun 19, 2018 at 10:31 PM Geoffry Roberts <[email protected]> wrote: >>>>>>>>>>>> >>>>>>>>>>>> I tried running Accumulo on Google. I first tried running it on Google's pre-made Hadoop. I found the various file paths one must contend with are different on Google than on a straight download from Apache. It seems they moved things around. To counter this, I installed my own Hadoop along with Zookeeper and Accumulo on a Google node. All went well until one fine day when I could no longer log in. It seems Google had pushed out some changes over night that broke my client side Google Cloud installation. Google referred the affected to a lengthy, easy-to-make-a-mistake procedure for resolving the issue. >>>>>>>>>>>> >>>>>>>>>>>> I decided life was too short for this kind of thing and switched to Amazon. >>>>>>>>>>>> >>>>>>>>>>>> On Tue, Jun 19, 2018 at 7:34 AM, Maxim Kolchin <[email protected]> wrote: >>>>>>>>>>>>> >>>>>>>>>>>>> Hi all, >>>>>>>>>>>>> >>>>>>>>>>>>> Does anyone have experience running Accumulo on top of Google Cloud Storage instead of HDFS? In [1] you can see some details if you never heard about this feature. >>>>>>>>>>>>> >>>>>>>>>>>>> I see some discussion (see [2], [3]) around this topic, but it looks to me that this isn't as popular as, I believe, should be. >>>>>>>>>>>>> >>>>>>>>>>>>> [1]: https://urldefense.proofpoint.com/v2/url?u=https-3A__cloud.google.com_dataproc_docs_concepts_connectors_cloud-2Dstorage&d=DwIFaQ&c=LFYZ-o9_HUMeMTSQicvjIg&r=tVgyCjxnNiJ0cjUcKRQFKA&m=Dh1LN-vxvgWAW9nDdnINj7ultMEGn6AjW4IGFLed30w&s=Ow_9xK5ABIEJsHBsXlCqQCJf63WEzC0RSrh1xTpVP5U&e= >>>>>>>>>>>>> [2]: https://urldefense.proofpoint.com/v2/url?u=https-3A__github.com_apache_accumulo_issues_428&d=DwIFaQ&c=LFYZ-o9_HUMeMTSQicvjIg&r=tVgyCjxnNiJ0cjUcKRQFKA&m=Dh1LN-vxvgWAW9nDdnINj7ultMEGn6AjW4IGFLed30w&s=98HiJiBLlqHr485MKj12gKhhd4wehE3n3VNWNCYYeH4&e= >>>>>>>>>>>>> [3]: https://urldefense.proofpoint.com/v2/url?u=https-3A__github.com_GoogleCloudPlatform_bigdata-2Dinterop_issues_103&d=DwIFaQ&c=LFYZ-o9_HUMeMTSQicvjIg&r=tVgyCjxnNiJ0cjUcKRQFKA&m=Dh1LN-vxvgWAW9nDdnINj7ultMEGn6AjW4IGFLed30w&s=2yPpLqw3V32UFtuTULJ4GIgrpBpvRT6k3sdvxxE7gys&e= >>>>>>>>>>>>> >>>>>>>>>>>>> Best regards, >>>>>>>>>>>>> Maxim >>>>>>>>>>>> >>>>>>>>>>>> >>>>>>>>>>>> >>>>>>>>>>>> >>>>>>>>>>>> -- >>>>>>>>>>>> There are ways and there are ways, >>>>>>>>>>>> >>>>>>>>>>>> Geoffry Roberts >>>>>>>>>> >>>>>>>>>> >>>>>>>>>> >>>>>>>>>> >>>>>>>>>> -- >>>>>>>>>> There are ways and there are ways, >>>>>>>>>> >>>>>>>>>> Geoffry Roberts >>>>>>>> >>>>>>>> >>>>>>
