{"id":87,"date":"2010-12-31T00:00:30","date_gmt":"2010-12-30T22:00:30","guid":{"rendered":"http:\/\/www.data-protector.org\/wordpress\/?p=87"},"modified":"2015-12-10T11:09:13","modified_gmt":"2015-12-10T10:09:13","slug":"was-ist-eigentlich-device-polling","status":"publish","type":"post","link":"https:\/\/www.data-protector.org\/wordpress\/2010\/12\/was-ist-eigentlich-device-polling\/","title":{"rendered":"What is device polling"},"content":{"rendered":"<p>Probably most customers using Data Protector with a Fibre Channel Tape Library attached expierienced this problem: a SCSI Reset during the backup including destroyed media. What happened? The drive was flooded with SCSI commands &#8211; device polling was the cause.<br \/>\nPolling is the behaviour of a service which polls tape drives and library controller via IFC (Interface Controller) or NSR (Network Storage Router) using SCSI commands frequently. This may influence running backups, as the NSR must process additional commands, which mostly come not from the backup software.<br \/>\nResults<\/p>\n<ul>\n<li>Changed backup speed<\/li>\n<li>I\/O errors<\/li>\n<li>The backup software recognizes the media as poor<\/li>\n<li>A tape drive will be set to offline<\/li>\n<li>The transfer rated decreases<\/li>\n<li>The tape drive can not stream<\/li>\n<\/ul>\n<p>Known serives causing these errors:<\/p>\n<ul>\n<li>Network scanner<\/li>\n<li>Removable Storage Manager<\/li>\n<li>Tape driver<\/li>\n<li>OVOSAM using old Tachyon drivers<\/li>\n<li>Insight Management Agents (SIM)<\/li>\n<li>Retrosopect \/ Retrorun (Macintosh)<\/li>\n<\/ul>\n<p>Recommendation: Deactivate polling on all servers where tape drives are attached.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Probably most customers using Data Protector with a Fibre Channel Tape Library attached expierienced this problem: a SCSI Reset during the backup including destroyed media. What happened? The drive was flooded with SCSI commands &#8211; device polling was the cause. Polling is the behaviour of a service which polls tape drives and library controller via [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_mi_skip_tracking":false,"spay_email":""},"categories":[1],"tags":[45,48,50,49,47,46],"translation":{"provider":"WPGlobus","version":"2.8.8","language":"en","enabled_languages":["en","de"],"languages":{"en":{"title":true,"content":true,"excerpt":false},"de":{"title":false,"content":true,"excerpt":false}}},"jetpack_featured_media_url":"","jetpack_shortlink":"https:\/\/wp.me\/p28cjj-1p","jetpack_sharing_enabled":true,"jetpack-related-posts":[{"id":100,"url":"https:\/\/www.data-protector.org\/wordpress\/2010\/12\/disable-device-polling\/","url_meta":{"origin":87,"position":0},"title":"Disable Device Polling","date":"31. December 2010","format":false,"excerpt":"{:de}In einem anderen Artikel \"What is device polling\" \u00a0hatte ich beschrieben was Device Polling ist und welche Auswirkungen das auf ein backup haben kann. Hier versuche ich nun aufzuzeigen wie man Device Polling verhindert. Bleibt zu erw\u00e4hnen das nachfolgende Hinweise f\u00fcr anst\u00e4ndige Hardware - HP - gelten. Wenn man gezwungen\u2026","rel":"","context":"In &quot;HowTo&quot;","img":{"alt_text":"","src":"","width":0,"height":0},"classes":[]},{"id":1478,"url":"https:\/\/www.data-protector.org\/wordpress\/2013\/07\/write-device-parameter-incorrect\/","url_meta":{"origin":87,"position":1},"title":"Cannot write to device &#8211; the parameter is incorrect","date":"5. July 2013","format":false,"excerpt":"{:en}When using the wrong block size for the tape devices, you may get the error message Cannot write to device ([87] The Parameter is incorrect.) during the backup or while formatting media. This error may occur if as SAS library, attached to the controller P212-ZM is used. When you try\u2026","rel":"","context":"In &quot;HowTo&quot;","img":{"alt_text":"","src":"","width":0,"height":0},"classes":[]},{"id":259,"url":"https:\/\/www.data-protector.org\/wordpress\/2011\/02\/problems-with-vepa-consolidated-packet-dpwin_00490\/","url_meta":{"origin":87,"position":2},"title":"Problems with VEPA Consolidated Packet &#8211; DPWIN_00490","date":"23. February 2011","format":false,"excerpt":"{:de}Wenn man den neuen VEPA Consolidated Packet - DPWIN_00490 (ehemals DPWIN_00483) installiert, so kann es vorkommen das bei der Sicherung die Devices nicht mehr angezeigt werden. Im Monitor sieht man die Session, jedoch werden keine Daten auf die Laufwerke (Bandlaufwerke, Filelibrary und Backupjob mit mit gespiegelten Laufwerken auf eine Filelibrary\u2026","rel":"","context":"In &quot;Bugs&quot;","img":{"alt_text":"","src":"","width":0,"height":0},"classes":[]},{"id":884,"url":"https:\/\/www.data-protector.org\/wordpress\/2012\/03\/drive-licenses\/","url_meta":{"origin":87,"position":3},"title":"Drive Licenses","date":"8. March 2012","format":false,"excerpt":"{:de}Ein beliebtes Thema und immer wieder angefragt: Welche Lizenzen muss ich f\u00fcr Laufwerke verwenden wenn eine FC Library f\u00fcr das Backup im Windows \/ Linux Umfeld an einem (1!) Server genutzt wird? Die Antowrt ist eigentlich einfach: Solange die Laufwerke nicht von verschiedenen Servern angesprochen werden und im Data Protector\u2026","rel":"","context":"In &quot;HowTo&quot;","img":{"alt_text":"","src":"","width":0,"height":0},"classes":[]},{"id":1862,"url":"https:\/\/www.data-protector.org\/wordpress\/2014\/03\/omnilistfreedevs-list-free-devices\/","url_meta":{"origin":87,"position":4},"title":"OMNILISTFREEDEVS 1.10 &#8211; get list of free devices","date":"7. March 2014","format":false,"excerpt":"{:en} Update: new version 1.10 does include a fix for multi-host and multipath configurations. In addition, the languages FRA, CHS and JPN are now supported (DP 8.0, 8.01 and 8.10). To get a list of free Data Protector devices can be a challenge, especially in larger environments. Of course, with\u2026","rel":"","context":"In &quot;SCD&quot;","img":{"alt_text":"","src":"","width":0,"height":0},"classes":[]},{"id":1365,"url":"https:\/\/www.data-protector.org\/wordpress\/2013\/05\/ipc-invalid-packet-size\/","url_meta":{"origin":87,"position":5},"title":"IPC Invalid Packet Size","date":"8. May 2013","format":false,"excerpt":"{:en}After the upgrade to DP 7.01 in some environments the rarley error IPC Invalid Packet Size has been seen while accessing a changer or tape device. The problem might be related to a slow name resolutuion on the media agent. The INET may run into a timeout before sending data\u2026","rel":"","context":"In &quot;HowTo&quot;","img":{"alt_text":"","src":"","width":0,"height":0},"classes":[]}],"_links":{"self":[{"href":"https:\/\/www.data-protector.org\/wordpress\/wp-json\/wp\/v2\/posts\/87"}],"collection":[{"href":"https:\/\/www.data-protector.org\/wordpress\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.data-protector.org\/wordpress\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.data-protector.org\/wordpress\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.data-protector.org\/wordpress\/wp-json\/wp\/v2\/comments?post=87"}],"version-history":[{"count":12,"href":"https:\/\/www.data-protector.org\/wordpress\/wp-json\/wp\/v2\/posts\/87\/revisions"}],"predecessor-version":[{"id":2745,"href":"https:\/\/www.data-protector.org\/wordpress\/wp-json\/wp\/v2\/posts\/87\/revisions\/2745"}],"wp:attachment":[{"href":"https:\/\/www.data-protector.org\/wordpress\/wp-json\/wp\/v2\/media?parent=87"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.data-protector.org\/wordpress\/wp-json\/wp\/v2\/categories?post=87"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.data-protector.org\/wordpress\/wp-json\/wp\/v2\/tags?post=87"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}