Excuse the ignorance, RCP?
On 24 October 2013 22:28, Jean-Marc Spaggiari <[email protected]>wrote: > Your nodes are almost 50% idle... Might be something else. Sound it's not > your disks nor your CPU... Maybe to many RCPs? > > Have you investigate on your network side? netperf might be a good help for > you. > > JM > > > 2013/10/24 Harry Waye <[email protected]> > > > p.s. I guess this is more turning into a general hadoop issue, but I'll > > keep the discussion here seeing that I have an audience, unless there are > > objections. > > > > > > On 24 October 2013 22:02, Harry Waye <[email protected]> wrote: > > > > > So just a short update, I'll read into it a little more tomorrow. This > > is > > > from three of the nodes: > > > https://gist.github.com/hazzadous/1264af7c674e1b3cf867 > > > > > > The first is the grey guy. Just glancing at it, it looks to fluctuate > > > more than the others. I guess that could suggest that there are some > > > issues with reading from the disks. Interestingly, it's the only one > > that > > > doesn't have smartd installed, which alerts us on changes for the other > > > nodes. I suspect there's probably some mileage in checking its smart > > > attributes. Will do that tomorrow though. > > > > > > Out of curiosity, how do people normally monitor disk issues? I'm > going > > > to set up collectd to push various things from smartctl tomorrow, at > the > > > moment all we do is receive emails, which is mostly noise about problem > > > sector counts increasing +1. > > > > > > > > > On 24 October 2013 19:40, Jean-Marc Spaggiari <[email protected] > > >wrote: > > > > > >> Can you try vmstat 2? 2 is the interval in seconds it will display the > > >> disk > > >> usage. On the extract here, nothing is running. only 8% is used. (1% > > disk > > >> IO, 6% User, 1% sys) > > >> > > >> Run it on 2 or 3 different nodes while you are putting the load on the > > >> cluster. And take a look at the 4 last numbers and see what the value > of > > >> the last one? > > >> > > >> On the usercpu0 graph, who is the gray guy showing hight? > > >> > > >> JM > > >> > > >> 2013/10/24 Harry Waye <[email protected]> > > >> > > >> > Ok I'm running a load job atm, I've add some possibly > incomprehensible > > >> > coloured lines to the graph: http://goo.gl/cUGCGG > > >> > > > >> > This is actually with one fewer nodes due to decommissioning to > > replace > > >> a > > >> > disk, hence I guess the reason for one squiggly line showing no disk > > >> > activity. I've included only the cpu stats for CPU0 from each node. > > >> The > > >> > last graph should read "Memory Used". vmstat from one of the nodes: > > >> > > > >> > procs -----------memory---------- ---swap-- -----io---- -system-- > > >> > ----cpu---- > > >> > r b swpd free buff cache si so bi bo in cs us > > sy > > >> id > > >> > wa > > >> > 6 0 0 392448 524668 43823900 0 0 501 1044 0 0 > 6 > > >> 1 > > >> > 91 1 > > >> > > > >> > To me the wait doesn't seem that high. Job stats are > > >> > http://goo.gl/ZYdUKp, the job setup is > > >> > https://gist.github.com/hazzadous/ac57a384f2ab685f07f6 > > >> > > > >> > Does anything jump out at you? > > >> > > > >> > Cheers > > >> > H > > >> > > > >> > > > >> > On 24 October 2013 16:16, Harry Waye <[email protected]> wrote: > > >> > > > >> > > Hi JM > > >> > > > > >> > > I took a snapshot on the initial run, before the changes: > > >> > > > > >> > > > >> > > > https://www.evernote.com/shard/s95/sh/b8e1516d-7c49-43f0-8b5f-d16bbdd3fe13/00d7c6cd6dd9fba92d6f00f90fb54fc1/res/4f0e20a2-1ecb-4085-8bc8-b3263c23afb5/screenshot.png > > >> > > > > >> > > Good timing, disks appear to be exploding (ATA errors) atm thus > I'm > > >> > > decommissioning and reprovisioning with new disks. I'll be > > >> > reprovisioning > > >> > > as without RAID (it's software RAID just to compound the issue) > > >> although > > >> > > not sure how I'll go about migrating all nodes. I guess I'd need > to > > >> put > > >> > > more correctly speced nodes in the rack and decommission the > > existing. > > >> > > Makes diff. to > > >> > > > > >> > > We're using hetzner at the moment which may not have been a good > > >> choice. > > >> > > Has anyone had any experience with them wrt. Hadoop? They offer > 7 > > >> and > > >> > 15 > > >> > > disk options, but are low on the cpu front (quad core). Our > > workload > > >> > will > > >> > > be I assume on the high side. There's also a 8 disk Dell > PowerEdge > > >> what > > >> > is > > >> > > a little more powerful. What hosting providers would people > > >> recommended? > > >> > > (And what would be the strategy for migrating?) > > >> > > > > >> > > Anyhow, when I have things more stable I'll have a look at > checking > > >> out > > >> > > what's using the cpu. In the mean time, can anything be gleamed > > from > > >> the > > >> > > above snap? > > >> > > > > >> > > Cheers > > >> > > H > > >> > > > > >> > > > > >> > > On 24 October 2013 15:14, Jean-Marc Spaggiari < > > >> [email protected] > > >> > >wrote: > > >> > > > > >> > >> Hi Harry, > > >> > >> > > >> > >> Do you have more details on the exact load? Can you run vmstats > and > > >> see > > >> > >> what kind of load it is? Is it user? cpu? wio? > > >> > >> > > >> > >> I suspect your disks to be the issue. There is 2 things here. > > >> > >> > > >> > >> First, we don't recommend RAID for the HDFS/HBase disk. The best > is > > >> to > > >> > >> simply mount the disks on 2 mounting points and give them to > HDFS. > > >> > >> Second, 2 disks per not is very low. On a dev cluster is not even > > >> > >> recommended. In production, you should go with 12 or more. > > >> > >> > > >> > >> So with only 2 disks in RAID, I suspect your WIO to be high which > > is > > >> > what > > >> > >> might slow your process. > > >> > >> > > >> > >> Can you take a look on that direction? If it's not that, we will > > >> > continue > > >> > >> to investigate ;) > > >> > >> > > >> > >> Thanks, > > >> > >> > > >> > >> JM > > >> > >> > > >> > >> > > >> > >> 2013/10/23 Harry Waye <[email protected]> > > >> > >> > > >> > >> > I'm trying to load data into hbase using HFileOutputFormat and > > >> > >> incremental > > >> > >> > bulk load but am getting rather lackluster performance, 10h for > > >> ~0.5TB > > >> > >> > data, ~50000 blocks. This is being loaded into a table that > has > > 2 > > >> > >> > families, 9 columns, 2500 regions and is ~10TB in size. Keys > are > > >> md5 > > >> > >> > hashes and regions are pretty evenly spread. The majority of > > time > > >> > >> appears > > >> > >> > to be spend in the reduce phase, with the map phase completing > > very > > >> > >> > quickly. The network doesn't appear to be saturated, but the > > load > > >> is > > >> > >> > consistently at 6 which is the number or reduce tasks per node. > > >> > >> > > > >> > >> > 12 hosts (6 cores, 2 disk as RAID0, 1GB eth, no one else on the > > >> rack). > > >> > >> > > > >> > >> > MR conf: 6 mappers, 6 reducers per node. > > >> > >> > > > >> > >> > I spoke to someone on IRC and they recommended reducing job > > output > > >> > >> > replication to 1, and reducing the number of mappers which I > > >> reduced > > >> > to > > >> > >> 2. > > >> > >> > Reducing replication appeared not to make any difference, > > reducing > > >> > >> > reducers appeared just to slow the job down. I'm going to > have a > > >> look > > >> > >> at > > >> > >> > running the benchmarks mentioned on Michael Noll's blog and see > > >> what > > >> > >> that > > >> > >> > turns up. I guess some questions I have are: > > >> > >> > > > >> > >> > How does the global number/size of blocks affect perf.? (I > have > > a > > >> lot > > >> > >> of > > >> > >> > 10mb files, which are the input files) > > >> > >> > > > >> > >> > How does the job local number/size of input blocks affect > perf.? > > >> > >> > > > >> > >> > What is actually happening in the reduce phase that requires so > > >> much > > >> > >> CPU? > > >> > >> > I assume the actual construction of HFiles isn't intensive. > > >> > >> > > > >> > >> > Ultimately, how can I improve performance? > > >> > >> > Thanks > > >> > >> > > > >> > >> > > >> > > > > >> > > > > >> > > > > >> > > -- > > >> > > Harry Waye, Co-founder/CTO > > >> > > [email protected] > > >> > > +44 7890 734289 > > >> > > > > >> > > Follow us on Twitter: @arachnys <https://twitter.com/#!/arachnys> > > >> > > > > >> > > --- > > >> > > Arachnys Information Services Limited is a company registered in > > >> England > > >> > & > > >> > > Wales. Company number: 7269723. Registered office: 40 Clarendon > St, > > >> > > Cambridge, CB1 1JX. > > >> > > > > >> > > > >> > > > >> > > > >> > -- > > >> > Harry Waye, Co-founder/CTO > > >> > [email protected] > > >> > +44 7890 734289 > > >> > > > >> > Follow us on Twitter: @arachnys <https://twitter.com/#!/arachnys> > > >> > > > >> > --- > > >> > Arachnys Information Services Limited is a company registered in > > >> England & > > >> > Wales. Company number: 7269723. Registered office: 40 Clarendon St, > > >> > Cambridge, CB1 1JX. > > >> > > > >> > > > > > > > > > > > > -- > > > Harry Waye, Co-founder/CTO > > > [email protected] > > > +44 7890 734289 > > > > > > Follow us on Twitter: @arachnys <https://twitter.com/#!/arachnys> > > > > > > --- > > > Arachnys Information Services Limited is a company registered in > England > > & > > > Wales. Company number: 7269723. Registered office: 40 Clarendon St, > > > Cambridge, CB1 1JX. > > > > > > > > > > > -- > > Harry Waye, Co-founder/CTO > > [email protected] > > +44 7890 734289 > > > > Follow us on Twitter: @arachnys <https://twitter.com/#!/arachnys> > > > > --- > > Arachnys Information Services Limited is a company registered in England > & > > Wales. Company number: 7269723. Registered office: 40 Clarendon St, > > Cambridge, CB1 1JX. > > > -- Harry Waye, Co-founder/CTO [email protected] +44 7890 734289 Follow us on Twitter: @arachnys <https://twitter.com/#!/arachnys> --- Arachnys Information Services Limited is a company registered in England & Wales. Company number: 7269723. Registered office: 40 Clarendon St, Cambridge, CB1 1JX.
