performance tuning a public mirror server - mike hulsman (proxy)

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Mike Hulsman (Proxy) on performance tuning a public mirror server. ftp.nluug.nl is a public mirror server running since the beginning of the 90′s, which currently transfers 4TB of data every day. This talk will provide some background on the service it provides. We discuss a history of the environment. In 2013, we chose to rebuild the server and we made some decisions. The process of performance tuning the ftp.nluug mirror server will be discussed, as well as how we got to the current performance.

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  • 1.NLUUG 15 May 2014 Performance tuning a public mirror server Mike Hulsman mike.hulsman@proxy.nl

2. NLUUG 15 May 2014 My background Been a sysadmin since 1990 Around 1995 started using Linux Since 2012 supporting ftp.nluug.nl Working @ Proxy in the Managed Services Team 3. NLUUG 15 May 2014 Hobby 4. NLUUG 15 May 2014 History of ftp.nluug.nl December 1992 total download 448575834 bytes 5. NLUUG 15 May 2014 Former hardware 2 servers round robin DNS All SCSI storage attached to 1 server Storage exported with NFS and GFS 6. NLUUG 15 May 2014 Current Hardware 1 server Xeon E3-1220 3.1 Ghz 16 GB Memory LSI Megaraid SAS 9271-4i 4 x 1GB ethernet 13 x 2TB disk, 12 disks in Raid5 1 hot spare drive 11 free positions for extra drives 7. NLUUG 15 May 2014 Performance servers 1 day avg Max 480 Mb/s Avg 160 Mb/s 2 TB/day Max 800 Mb/s Avg 340 Mb/s 4 TB/day The current server The 2 servers 8. NLUUG 15 May 2014 What we serve 17 TB of used storage 13.800.038 files 12.224.856 files smaller than 1 MB 681.468 directories 1.606.561 links (hard and soft links) 9. NLUUG 15 May 2014 Max of TB/month Jun 2013 Oct 2013 Apr 2008 May 2013 Nov 2013 Feb 2014 Mar 2014 Dec 2013 Jan 2014 Apr 2014 0 20 40 60 80 100 120 140 93.67 94.61 94.66 96.43 103.94 109.47 117.63 118.05 119.84 128.62 TB/month 10. NLUUG 15 May 2014 Atoptool with netatop Atoptool together with netatop kernel module 11. NLUUG 15 May 2014 Mrtg 12. NLUUG 15 May 2014 Munin 13. NLUUG 15 May 2014 Nagios 14. NLUUG 15 May 2014 Design decisions new server Machine is I/O based not CPU or Memory Disk I/O should be as fast as possible 4 x 1 Gb ethernet cards in bonding mode Is a public mirror server, downtime is not critical Costs effective, whole server including disks costed about 5K 15. NLUUG 15 May 2014 Raid setup Machine build was in november 2012 Hitachi Ultrastar 7k3000 2 TB drives 2.0 million hours MTBF, 5 years guaranty 64 MB cache LSI MegaRAID SAS 9271-4i Card 1 Gb cache memory CacheVault, NV Flash cache and battery 256kB Stripe size 12 disks in Raid5 1 hot spare 16. NLUUG 15 May 2014 What was changed 17. NLUUG 15 May 2014 Problem #1 4 x 1Gb ethernet interfaces Bonded as balance-alb Send and receive are bonded Did not work out as we thought. Maximum speed of all interfaces together did not exceed 960 Mb/s In June 2013 together with Surfnet assistance moved to 802.3ad and xmit_hash_policy=layer3+4 With atop we could see that the balancing is working Did not work out as aspected Maximum speed at that time was 993 Mb/s 18. NLUUG 15 May 2014 Solution Changes in the bonding parameters Upgraded / downgraded ethernet driver versions Tuning kernel parameters Crap said the Surfnet engineer ;-) Connection to a Cisco module where 8 ports have only a 1 Gb/s backend port. We were on ports Gi9/3 Gi9/4 Gi9/5 Gi9/6 After rerouting ports (Gi9/3 Gi9/11 Gi9/17 Gi9/28) peaks of 2.4 Gb/s were seen 19. NLUUG 15 May 2014 The whole process of tuning At first I did not document, only implement Now I document what I changed, including time stamp Buffers were too small Timeout's were too long Did not know where to start So many performance tuning articles The problem with a public mirror server is that it is public I even changed parameters while writing this presentation 20. NLUUG 15 May 2014 Firewall Lot's of messages ip_conntrack: table full net.netfilter.nf_conntrack_max = 1048576 wc -l /proc/net/nf_conntrack net.netfilter.nf_conntrack_tcp_timeout_established = 600 Defaults are 432000 (5 day's) 21. NLUUG 15 May 2014 We can get troughput 22. NLUUG 15 May 2014 Networking buffers Ethtool -G ethx rx 4096 tx 4096 Ifconfig ethx txqueuelen 20000 Also for bonding interface (not sure if needed) Ethtool -K ethx gso on (generic-segmentation-offload) Ethtool -K ethx gro on (generic-receive-offload) 23. NLUUG 15 May 2014 Filesystems Limited to 3TB filesystems Echo noop > /sys/block/sda/queue/scheduler Also tried deadline All are ext4 options noatime,nodiratime,noacl,commit=15 LSI CacheFlushInterval=10 (default 5) 24. NLUUG 15 May 2014 OS level irqbalance to oneshot Chkconfig del cpuspeed; service stop cpuspeed vm.min_free_kbytes=204800 To prevent out of memory errors Prevent deadlocks under high loads Ulimit Max openfiles 25. NLUUG 15 May 2014 Yum-plugin-fastestmirror centos.mirror1.spango.com 1.624 ms ftp.nluug.nl 1.533 ms mirror.prolocation.net 1.44 ms mirror.widexs.nl 1.371 ms Add prefer=ftp.nluug.nl to /etc/yum/pluginconf.d/fastestmirror.conf 26. NLUUG 15 May 2014 Application level Rsync just the standards Vsftpd just the standards Apache 2.2.15 Were running 4 instances, 1 for every IPv4 and Ipv6 Reduce now to 1 instance KeepAlive On MaxKeepAliveRequests 1000 ServerLimit 1024 MaxClients 1024 MaxRequestsPerChild 800 27. NLUUG 15 May 2014 Future Hardware Memory from 16GB to 32 GB Add more opensource projects Than we need more disks Nginx Maybe I should try XFS in the future We just need more hits !! 28. NLUUG 15 May 2014 Some of the mirrors Most Linux distributions are mirrored (currently 163 different) BSD (FreeBSD, NetBSD, OpenBSD Openindiana, opensolaris, illumos Jenkins Mariadb Vim Blender, gimp, ImageMagick Apache Qt , perl, gcc Vlc, xbmc, openelec 29. NLUUG 15 May 2014 Questions...... mike.hulsman@proxy.nl ftp-admin@nluug.nl 30. NLUUG 15 May 2014 List of URL's https://github.com/jeffmurphy/NetPass/blob/master/doc/netfilter https://gist.github.com/kfox/1942782 http://www.atoptool.nl/ http://www.bufferbloat.net/attachments/9/BufferBloat11.pdf http://lwn.net/Articles/507065/ http://www.coverfire.com/articles/queueing-in-the-linux-network-