# BIG-IP : sync-failover device-group sync options **URL:** \ **Category:** Technical Forums\ **Tags:** availability, cluster, big-ip, config-sync\ **Created:** [October 28, 2014, 7:29pm UTC](https://community.f5.com/t/big-ip-sync-failover-device-group-sync-options/17937 "2014-10-28T19:29:46Z")\ **Posts on this page:** 9\ **Page:** 1
**Author:** ![BaltoStar\_12467](https://avatars.discourse-cdn.com/v4/letter/b/df705f/32.png) [@BaltoStar\_12467](https://community.f5.com/u/BaltoStar_12467)\ **Post date:** [October 28, 2014, 7:29pm UTC](https://community.f5.com/t/big-ip-sync-failover-device-group-sync-options/17937/1 "2014-10-28T19:29:46Z")
F5 BIG-IP Virtual Edition v11.4.1 (Build 635.0) LTM on ESXi For a device-group of type sync-failover, the admin browser provides these options : ```tcl Automatic Sync Full Sync Maximum Incremental Sync Size (KB) ``` Could someone please explain these options ? Are syncs on a time-schedule ? Or are syncs triggered by any change to the primary ? Or exactly what types of changes will trigger a sync ? Specifically, will a change to a data-group file ( e.g. add/delete a line ) trigger a sync ? ---
**Author:** ![NikhilB\_149913](https://avatars.discourse-cdn.com/v4/letter/n/a8b319/32.png) [@NikhilB\_149913](https://community.f5.com/u/NikhilB_149913)\ **Post date:** [October 29, 2014, 3:30am UTC](https://community.f5.com/t/big-ip-sync-failover-device-group-sync-options/17937/2 "2014-10-29T03:30:31Z")
Automatic Sync - Sync is automatic and not manual. Done almost immediatelly after a change is made Full Sync - if checked will do a FULL sync and if left unchecked, only an incremental sync Maximum Incremental Sync Size (KB) - 1024 - if you make more than this default value it goes into FullSync mode. (number is a variable) [support.f5.com](http://support.f5.com) has further info on this. Hope this helps for now. ---
**Author:** ![NikhilB](https://avatars.discourse-cdn.com/v4/letter/n/4bbf92/32.png) [@NikhilB](https://community.f5.com/u/NikhilB)\ **Post date:** [October 29, 2014, 3:30am UTC](https://community.f5.com/t/big-ip-sync-failover-device-group-sync-options/17937/3 "2014-10-29T03:30:31Z")
Automatic Sync - Sync is automatic and not manual. Done almost immediatelly after a change is made Full Sync - if checked will do a FULL sync and if left unchecked, only an incremental sync Maximum Incremental Sync Size (KB) - 1024 - if you make more than this default value it goes into FullSync mode. (number is a variable) [support.f5.com](http://support.f5.com) has further info on this. Hope this helps for now. ---
**Author:** ![BaltoStar\_12467](https://avatars.discourse-cdn.com/v4/letter/b/df705f/32.png) [@BaltoStar\_12467](https://community.f5.com/u/BaltoStar_12467)\ **Post date:** [November 20, 2014, 12:46am UTC](https://community.f5.com/t/big-ip-sync-failover-device-group-sync-options/17937/4 "2014-11-20T00:46:13Z")
thanks NikhilB .. what would motivate a full-sync vs an incremental-sync ? are there scenarios where an incremental-sync is not fully reliable ? ---
**Author:** ![BaltoStar\_12467](https://avatars.discourse-cdn.com/v4/letter/b/df705f/32.png) [@BaltoStar\_12467](https://community.f5.com/u/BaltoStar_12467)\ **Post date:** [November 20, 2014, 12:46am UTC](https://community.f5.com/t/big-ip-sync-failover-device-group-sync-options/17937/5 "2014-11-20T00:46:13Z")
thanks NikhilB .. what would motivate a full-sync vs an incremental-sync ? are there scenarios where an incremental-sync is not fully reliable ? ---
**Author:** ![Zdenda](https://avatars.discourse-cdn.com/v4/letter/z/ac8455/32.png) [@Zdenda](https://community.f5.com/u/Zdenda)\ **Post date:** [June 4, 2016, 9:28am UTC](https://community.f5.com/t/big-ip-sync-failover-device-group-sync-options/17937/6 "2016-06-04T09:28:53Z")
Hi, opening this after some time… I am also curious what would motivate you to select full-sync over incremental-sync? ---
**Author:** ![Zdenda](https://avatars.discourse-cdn.com/v4/letter/z/ac8455/32.png) [@Zdenda](https://community.f5.com/u/Zdenda)\ **Post date:** [June 4, 2016, 9:28am UTC](https://community.f5.com/t/big-ip-sync-failover-device-group-sync-options/17937/7 "2016-06-04T09:28:53Z")
Hi, opening this after some time… I am also curious what would motivate you to select full-sync over incremental-sync? ---
**Author:** ![Yann\_Desmarest\_1](https://avatars.discourse-cdn.com/v4/letter/y/65b543/32.png) [@Yann\_Desmarest\_1](https://community.f5.com/u/Yann_Desmarest_1)\ **Post date:** [June 4, 2016, 1:16pm UTC](https://community.f5.com/t/big-ip-sync-failover-device-group-sync-options/17937/8 "2016-06-04T13:16:55Z")
Hi, we forced full-sync over incremental-sync because we get lot of issues with incremental since we are using many iapps. There is a known issue and should have been fixed in latest bigip version. ---
**Author:** ![Yann\_Desmarest\_1](https://avatars.discourse-cdn.com/v4/letter/y/65b543/32.png) [@Yann\_Desmarest\_1](https://community.f5.com/u/Yann_Desmarest_1)\ **Post date:** [June 4, 2016, 1:16pm UTC](https://community.f5.com/t/big-ip-sync-failover-device-group-sync-options/17937/9 "2016-06-04T13:16:55Z")
Hi, we forced full-sync over incremental-sync because we get lot of issues with incremental since we are using many iapps. There is a known issue and should have been fixed in latest bigip version.