{"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":3016,"url":"https:\/\/www.data-protector.org\/wordpress\/2016\/05\/prepare-and-execute-eadr-cell-server-on-windows-2012-r2-data-protector-9-06\/","url_meta":{"origin":87,"position":1},"title":"Prepare and execute EADR &#8211; Cell Server on Windows 2012 R2 and Data Protector 9.06","date":"13. May 2016","format":false,"excerpt":"{:en} In the past I often informed about the free EADR feature in Data Protector to recover clients and cell server. The last time I wrote an article in 2014 including two small scripts to get things prepared and automated - see https:\/\/www.data-protector.org\/wordpress\/2014\/04\/eadr-cell-server-dp-8-1x-windows-2012-r2\/. However, the batch files got broken due\u2026","rel":"","context":"In &quot;HowTo&quot;","img":{"alt_text":"EADR_23","src":"https:\/\/i0.wp.com\/www.data-protector.org\/wordpress\/wp-content\/uploads\/2016\/05\/EADR_23.png?resize=350%2C200&ssl=1","width":350,"height":200},"classes":[]},{"id":1345,"url":"https:\/\/www.data-protector.org\/wordpress\/2013\/05\/persistent-binding-hp-lto-tape-drives-windows\/","url_meta":{"origin":87,"position":2},"title":"Persistent Binding for HP LTO tape drives on Windows","date":"8. May 2013","format":false,"excerpt":"{:en}\"Tape Persistence\" means that the tape drives for a tape library use symbolic names. These names stay unique during server reboots, no matter in which order the operating system discovers the tape drives. Without the feature during reboots it could be possible that the SCSI addresses are changed. Normally the\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":3},"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":1819,"url":"https:\/\/www.data-protector.org\/wordpress\/2014\/01\/storeonce-success-story-australia\/","url_meta":{"origin":87,"position":4},"title":"StoreOnce success story from Australia","date":"27. January 2014","format":false,"excerpt":"{:en}Recently I asked you to share your StoreOnce success story. Here is a awesome story and a good example for federated deduplication from a company in Australia. Before using HP StoreOnce, the company used to protect its data in the two datacentres using HP Data Protector. The data (FileSystems, MS\u2026","rel":"","context":"In &quot;SCD&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":5},"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":[]}],"_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}]}}