└── README.md /README.md: -------------------------------------------------------------------------------- 1 | # awesome limits 2 | 3 | ## Preamble 4 | 5 | Everything has limits, including software systems. When you hit these limits, bad things can happen. 6 | 7 | You've probably hit memory and disk limits, but those aren't the only ones. 8 | 9 | This page lists limits that, when breached, led to someone having a bad time. I [tweeted](https://twitter.com/lhochstein/status/1332781588246097927) about limits and 10 | got all sorts of interesting responses. This page contains some of them, with links to the tweets, which often contain more details. 11 | 12 | ## Examples of limits that have been breached with ill consequences 13 | 14 | inodes. [@aegis](https://twitter.com/ageis/status/1332931216014790656), [Alex Elman](https://twitter.com/_pkill/status/1332784570371100674), [Benjamin Stein](https://twitter.com/benstein/status/1332840496956260354), [Thomas Attree](https://twitter.com/attree/status/1332986131068186629), [@dmolnar](https://twitter.com/dmolnar/status/1332788022232936450), [@anotherwalther](https://twitter.com/anotherwalther/status/1332785877811142659), [Jinsy Oommen](https://twitter.com/thegoodoommen/status/1332797783552765967), [Rafael Jesus](https://twitter.com/_jesus_rafael/status/1332799734302584834), [Ondrej Kokes](https://twitter.com/pndrej/status/1333132013231026178), [Peter Wang](https://twitter.com/pwang/status/1333038343416934403), [Cadey A. Ratio](https://twitter.com/theprincessxena/status/1333017957514043392), [@williamsjoe](https://twitter.com/williamsjoe/status/1332829443748896768), [Nic Wise](https://twitter.com/fastchicken/status/1332821356681994240), [ericdennis](https://twitter.com/ericdennis/status/1332796988429983744) 15 | 16 | 17 | open file descriptors / handles. [Moritz Lenz](https://twitter.com/nogoodnickleft/status/1333129430424805376), [Matt McDonald](https://twitter.com/overstood/status/1332971151413284866), [@aegis](https://twitter.com/ageis/status/1332931216014790656), [Bruno Félix](https://twitter.com/felix19350/status/1332792700882575361), [Ken Carroll](https://twitter.com/Crumlinfinglas/status/1332809128398512130), [@ehashdn](https://twitter.com/ehashdn/status/1332820368868839425), [Jeff Bean](https://twitter.com/jwfbean/status/1332801837188071425), [@patriotvn](https://twitter.com/patriotvn/status/1332801416986025989), [Peter Wang](https://twitter.com/pwang/status/1333038343416934403), [@asm0dio](https://twitter.com/asm0di0/status/1333027981393063940), [@williamsjoe](https://twitter.com/williamsjoe/status/1332829443748896768), [ericdennis](https://twitter.com/ericdennis/status/1332796988429983744), [Jakub Korab](https://twitter.com/jakekorab/status/1332791724146647040) 18 | 19 | 20 | processes (pids). [@RuinTaughtMe](https://twitter.com/RuinTaughtMe/status/1332799858722238464), [@patriotvn](https://twitter.com/patriotvn/status/1332801416986025989), [Matt Tex Ackerle](https://twitter.com/MattTexEckerle/status/1333043006820282368), [@pete23com](https://twitter.com/pete23com/status/1332783470632984581) 21 | 22 | Ports. [@qudooschaudhry](https://twitter.com/qudooschaudhry), [Alex Hidalgo](https://twitter.com/ahidalgosre/status/1332782613279502338), [Rafael Jesus](https://twitter.com/_jesus_rafael/status/1332799734302584834), [@williamsjoe](https://twitter.com/williamsjoe/status/1332829443748896768) 23 | 24 | TCP connections. [Sheeri K. Cabral](https://twitter.com/sheeri/status/1332882656200159232), [@Pluto_Berlin](https://twitter.com/Pluto_Berlin/status/1332842844751585281) 25 | 26 | Threads. [@dbsmasher](https://twitter.com/dbsmasher/status/1332787577934344192), [David Bezley](https://twitter.com/dabeaz/status/1333054692633563139) 27 | 28 | Entropy pool. [Justin Manchester](https://twitter.com/JuMaUK/status/1332798142958477316), [Petru Ratiu](https://twitter.com/rpetre/status/1332798387398340609) 29 | 30 | Shebang length. [@bengerman13](https://twitter.com/bengerman13/status/1332794119094153221), [Anthony Sottile](https://twitter.com/codewithanthony/status/1332832546086797312?s=20) 31 | 32 | Virtual memory. [@shanemhansen](https://twitter.com/shanemhansen/status/1332812554251321344), [@williamsjoe](https://twitter.com/williamsjoe/status/1332829443748896768) 33 | 34 | How fast the kernel can find an unused port to allocate a new connection. [Sean Kilgore](https://twitter.com/log1kal/status/1332862515135401984) 35 | 36 | Pod memory limits. [@dastbe](https://twitter.com/dastbe/status/1332828656515784704) 37 | 38 | Environment variable size. [Glen Mailer](https://twitter.com/glenathan/status/1333033938038747136) 39 | 40 | Java ring buffer size. [Richard Tibbetts](https://twitter.com/tibbetts/status/1332808950027268096) 41 | 42 | .NET framework threadpool I/O completion port limit. [Brandon Paddock](https://twitter.com/BrandonLive/status/1333102381597245441) 43 | 44 | SQL Server buffer cache. [Dave Poole](https://twitter.com/DavidJPoole/status/1332958574214049794) 45 | 46 | Concurrency limit of Java concurrent hash map. [Matt McDonald](https://twitter.com/overstood/status/1332971151413284866) 47 | 48 | ulimit on number of processes that can be run per user. [Ben Hemphill](https://twitter.com/benhemphill/status/1332799141236367360) 49 | 50 | memlock with JVM. [@aegis](https://twitter.com/ageis/status/1332931216014790656) 51 | 52 | IOPs [Arie Kachler](https://twitter.com/akachler/status/1332809935932035073), [Jesse Noller](https://twitter.com/jessenoller/status/1332788536890720256) 53 | 54 | System time divergence. [Nicolai von Neudeck](https://twitter.com/vonneudeck/status/1332797263249371136) 55 | 56 | Goroutines. [@beccadottex](https://twitter.com/beccadottex/status/1332824960453144576) 57 | 58 | 59 | Number of fields in an elastic search index. [@bengerman13](https://twitter.com/bengerman13/status/1332794119094153221) 60 | 61 | Filename / path size limit, on Windows. [@BennettElder](https://twitter.com/BennettElder/status/1332790932568215552), [Peter Wang](https://twitter.com/pwang/status/1333038343416934403) 62 | 63 | Number of vlans in vmware vcloud director, 2015 edition. [Jose manuel de arce](https://twitter.com/j0sema/status/1332956583190466560) 64 | 65 | 66 | ipconntrack. [@shanemhansen](https://twitter.com/shanemhansen/status/1332812778826989570), [Glen Mailer](https://twitter.com/glenathan/status/1332784414137397252) 67 | 68 | Load balancer license connection limits. [Franklin Wirtz](https://twitter.com/franklinwirtz/status/1332793886595444736) 69 | 70 | Wal senders. [Max Knee](https://twitter.com/maxknee/status/1332851399026208768) 71 | 72 | Kernel udp rx buffer size. [@sjoeboo](https://twitter.com/sjoeboo/status/1332800957760081924) 73 | 74 | Network bandwidth. [@anotherwalther](https://twitter.com/anotherwalther/status/1332785877811142659), [Rafael Jesus](https://twitter.com/_jesus_rafael/status/1332799734302584834) 75 | 76 | AWS API limit on number of requests made per minute when requesting new instances. [Justin Manchester](https://twitter.com/JuMaUK/status/1332801575421669379) 77 | 78 | Number of links to a file. [@mendel](https://twitter.com/mendel/status/1332807569384103940) 79 | 80 | Number of files per directory. [@hlieberman](https://twitter.com/hlieberman/status/1332796977407533059) 81 | 82 | VPC DNS packet limits. [Rafael Jesus](https://twitter.com/_jesus_rafael/status/1332799734302584834) 83 | 84 | Number of huge pages. [@patriotvn](https://twitter.com/patriotvn/status/1332801416986025989) 85 | 86 | Connections to Oracle database. [Viktor Gamov](https://twitter.com/gAmUssA/status/1332914886075174912) 87 | 88 | Socket filename length limit. [Anthony Sottile](https://twitter.com/codewithanthony/status/1332832546086797312?s=20) 89 | 90 | Stack size. [@williamsjoe](https://twitter.com/williamsjoe/status/1332829443748896768) 91 | 92 | Buffer exhaustion in NICs & switches. [@williamsjoe](https://twitter.com/williamsjoe/status/1332829443748896768) 93 | 94 | AWS EC2 instance count limits. [Nic Wise](https://twitter.com/fastchicken/status/1332821356681994240) 95 | 96 | Time Wait Assasination. [John Allspaw](https://twitter.com/allspaw/status/1332789693474332674) 97 | 98 | Semaphores. [@rknayyar](https://twitter.com/rknayyar/status/1333003544903954434) 99 | 100 | Number of OS threads. [AWS 2020-11-25](https://aws.amazon.com/message/11201/) 101 | --------------------------------------------------------------------------------