Re: [ceph-users] advice with erasure coding
VMs on erasure coded SSDs with fast_read work fine since 12.2.2. Paul Am Sa., 8. Sep. 2018 um 18:17 Uhr schrieb David Turner : > > I tested running VMs on EC back in Hammer. The performance was just bad. I > didn't even need much io, but even performing standard maintenance was > annoying enough that I abandoned the idea. I didn't really try to tweak > settings to make it work and I only had a 3 node cluster running 2+1. I did > use it for write once/read many data volumes which worked great. I eventually > moved away from that on RBDs and migrated into EC on CephFS once that became > stable in Jewel. Now on Luminous I've even been able to remove the cache tier > I once had in front of all of the EC things. > > On Fri, Sep 7, 2018, 5:19 PM Maged Mokhtar wrote: >> >> On 2018-09-07 13:52, Janne Johansson wrote: >> >> >> >> Den fre 7 sep. 2018 kl 13:44 skrev Maged Mokhtar : >>> >>> >>> Good day Cephers, >>> >>> I want to get some guidance on erasure coding, the docs do state the >>> different plugins and settings but to really understand them all and their >>> use cases is not easy: >>> >>> -Are the majority of implementations using jerasure and just configuring k >>> and m ? >> >> >> Probably, yes >> >>> >>> -For jerasure: when/if would i need to change >>> stripe_unit/osd_pool_erasure_code_stripe_unit/packetsize/algorithm ? The >>> main usage is rbd with 4M object size, the workload is virtualization with >>> average block size of 64k. >>> >>> Any help based on people's actual experience will be greatly appreciated.. >>> >>> >> >> Running VMs on top of EC pools is possible, but probably not recommended. >> All the random reads and writes they usually cause will make EC less >> suitable than replicated pools, even if it is possible. >> >> -- >> May the most significant bit of your life be positive. >> >> Point well taken...it could be useful for backing up vms, and maybe vms >> without too much latency requirements if k and m are not large. >> >> ___ >> ceph-users mailing list >> ceph-users@lists.ceph.com >> http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com > > ___ > ceph-users mailing list > ceph-users@lists.ceph.com > http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com -- Paul Emmerich Looking for help with your Ceph cluster? Contact us at https://croit.io croit GmbH Freseniusstr. 31h 81247 München www.croit.io Tel: +49 89 1896585 90 ___ ceph-users mailing list ceph-users@lists.ceph.com http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com
Re: [ceph-users] advice with erasure coding
I tested running VMs on EC back in Hammer. The performance was just bad. I didn't even need much io, but even performing standard maintenance was annoying enough that I abandoned the idea. I didn't really try to tweak settings to make it work and I only had a 3 node cluster running 2+1. I did use it for write once/read many data volumes which worked great. I eventually moved away from that on RBDs and migrated into EC on CephFS once that became stable in Jewel. Now on Luminous I've even been able to remove the cache tier I once had in front of all of the EC things. On Fri, Sep 7, 2018, 5:19 PM Maged Mokhtar wrote: > On 2018-09-07 13:52, Janne Johansson wrote: > > > > Den fre 7 sep. 2018 kl 13:44 skrev Maged Mokhtar : > >> >> Good day Cephers, >> >> I want to get some guidance on erasure coding, the docs do state the >> different plugins and settings but to really understand them all and their >> use cases is not easy: >> >> -Are the majority of implementations using jerasure and just configuring >> k and m ? >> > > Probably, yes > > >> -For jerasure: when/if would i need to change >> stripe_unit/osd_pool_erasure_code_stripe_unit/packetsize/algorithm ? The >> main usage is rbd with 4M object size, the workload is virtualization with >> average block size of 64k. >> >> Any help based on people's actual experience will be greatly appreciated.. >> >> >> > Running VMs on top of EC pools is possible, but probably not recommended. > All the random reads and writes they usually cause will make EC less > suitable than replicated pools, even if it is possible. > > -- > May the most significant bit of your life be positive. > > Point well taken...it could be useful for backing up vms, and maybe vms > without too much latency requirements if k and m are not large. > ___ > ceph-users mailing list > ceph-users@lists.ceph.com > http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com > ___ ceph-users mailing list ceph-users@lists.ceph.com http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com
Re: [ceph-users] advice with erasure coding
On 2018-09-07 13:52, Janne Johansson wrote: > Den fre 7 sep. 2018 kl 13:44 skrev Maged Mokhtar : > >> Good day Cephers, >> >> I want to get some guidance on erasure coding, the docs do state the >> different plugins and settings but to really understand them all and their >> use cases is not easy: >> >> -Are the majority of implementations using jerasure and just configuring k >> and m ? > > Probably, yes > >> -For jerasure: when/if would i need to change >> stripe_unit/osd_pool_erasure_code_stripe_unit/packetsize/algorithm ? The >> main usage is rbd with 4M object size, the workload is virtualization with >> average block size of 64k. >> >> Any help based on people's actual experience will be greatly appreciated.. > > Running VMs on top of EC pools is possible, but probably not recommended. > All the random reads and writes they usually cause will make EC less suitable > than replicated pools, even if it is possible. > -- > May the most significant bit of your life be positive. Point well taken...it could be useful for backing up vms, and maybe vms without too much latency requirements if k and m are not large.___ ceph-users mailing list ceph-users@lists.ceph.com http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com
Re: [ceph-users] advice with erasure coding
Den fre 7 sep. 2018 kl 13:44 skrev Maged Mokhtar : > > Good day Cephers, > > I want to get some guidance on erasure coding, the docs do state the > different plugins and settings but to really understand them all and their > use cases is not easy: > > -Are the majority of implementations using jerasure and just configuring k > and m ? > Probably, yes > -For jerasure: when/if would i need to change > stripe_unit/osd_pool_erasure_code_stripe_unit/packetsize/algorithm ? The > main usage is rbd with 4M object size, the workload is virtualization with > average block size of 64k. > > Any help based on people's actual experience will be greatly appreciated.. > > Running VMs on top of EC pools is possible, but probably not recommended. All the random reads and writes they usually cause will make EC less suitable than replicated pools, even if it is possible. -- May the most significant bit of your life be positive. ___ ceph-users mailing list ceph-users@lists.ceph.com http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com
[ceph-users] advice with erasure coding
Good day Cephers, I want to get some guidance on erasure coding, the docs do state the different plugins and settings but to really understand them all and their use cases is not easy: -Are the majority of implementations using jerasure and just configuring k and m ? -For jerasure: when/if would i need to change stripe_unit/osd_pool_erasure_code_stripe_unit/packetsize/algorithm ? The main usage is rbd with 4M object size, the workload is virtualization with average block size of 64k. Any help based on people's actual experience will be greatly appreciated.. /Maged___ ceph-users mailing list ceph-users@lists.ceph.com http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com
