Thanks a lot David, for me is a little bit difficult to make some tests because I have to buy a hardware... and the price is different with cache ssd tier o without it.
If anybody have experience with VDI/login storms... will be really welcome! Note: I have removed the ceph-user list because I get errors when I copy it. 2017-08-18 2:20 GMT+02:00 David Turner <drakonst...@gmail.com>: > Get it set up and start running tests. You can always enable or disable > the cache tier later. I don't know if Christian will chime in. And please > stop removing the ceph-users list from your responses. > > On Thu, Aug 17, 2017, 7:41 PM Oscar Segarra <oscar.sega...@gmail.com> > wrote: > >> Thanks a lot David!!! >> >> Let's wait the opinion of Christian about the suggested configuration for >> VDI... >> >> Óscar Segarra >> >> 2017-08-18 1:03 GMT+02:00 David Turner <drakonst...@gmail.com>: >> >>> `ceph df` and `ceph osd df` should give you enough information to know >>> how full each pool, root, osd, etc are. >>> >>> On Thu, Aug 17, 2017, 5:56 PM Oscar Segarra <oscar.sega...@gmail.com> >>> wrote: >>> >>>> Hi David, >>>> >>>> Thanks a lot again for your quick answer... >>>> >>>> >>>> *The rules in the CRUSH map will always be followed. It is not >>>> possible for Ceph to go against that and put data into a root that >>>> shouldn't have it.* >>>> --> I will work on your proposal of creating two roots in the CRUSH >>>> map... just one question more: >>>> --> Regarding to space consumption, with this proposal, is it possible >>>> to know how many disk space is it free in each pool? >>>> >>>> >>>> *The problem with a cache tier is that Ceph is going to need to promote >>>> and evict stuff all the time (not free). A lot of people that want to use >>>> SSD cache tiering for RBDs end up with slower performance because of this. >>>> Christian Balzer is the expert on Cache Tiers for RBD usage. His primary >>>> stance is that it's most likely a bad idea, but there are definite cases >>>> where it's perfect.* >>>> --> Christian, is there any advice for VDI --> BASE IMAGE (raw) + 1000 >>>> linked clones (qcow2) >>>> >>>> Thanks a lot. >>>> >>>> >>>> 2017-08-17 22:42 GMT+02:00 David Turner <drakonst...@gmail.com>: >>>> >>>>> The rules in the CRUSH map will always be followed. It is not >>>>> possible for Ceph to go against that and put data into a root that >>>>> shouldn't have it. >>>>> >>>>> The problem with a cache tier is that Ceph is going to need to promote >>>>> and evict stuff all the time (not free). A lot of people that want to use >>>>> SSD cache tiering for RBDs end up with slower performance because of this. >>>>> Christian Balzer is the expert on Cache Tiers for RBD usage. His primary >>>>> stance is that it's most likely a bad idea, but there are definite cases >>>>> where it's perfect. >>>>> >>>>> >>>>> On Thu, Aug 17, 2017 at 4:20 PM Oscar Segarra <oscar.sega...@gmail.com> >>>>> wrote: >>>>> >>>>>> Hi David, >>>>>> >>>>>> Thanks a lot for your quick answer! >>>>>> >>>>>> *If I'm understanding you correctly, you want to have 2 different >>>>>> roots that pools can be made using. The first being entirely SSD >>>>>> storage. >>>>>> The second being HDD Storage with an SSD cache tier on top of it. * >>>>>> --> Yes, this is what I mean. >>>>>> >>>>>> https://www.sebastien-han.fr/blog/2014/08/25/ceph-mix-sata- >>>>>> and-ssd-within-the-same-box/ >>>>>> --> I'm not an expert in CRUSH rules... Whit this configuration, it >>>>>> is guaranteed that objects stored in ssd pool do not "go" to the hdd >>>>>> disks? >>>>>> >>>>>> *The above guide explains how to set up the HDD root and the SSD >>>>>> root. After that all you do is create a pool on the HDD root for RBDs, a >>>>>> pool on the SSD root for a cache tier to use with the HDD pool, and then >>>>>> a >>>>>> a pool on the SSD root for RBDs. There aren't actually a lot of use >>>>>> cases >>>>>> out there where using an SSD cache tier on top of an HDD RBD pool is what >>>>>> you really want. I would recommend testing this thoroughly and comparing >>>>>> your performance to just a standard HDD pool for RBDs without a cache >>>>>> tier.* >>>>>> --> I'm working on a VDI solution where there are BASE IMAGES (raw) >>>>>> and qcow2 linked clones... where I expect not all VDIs to be powered on >>>>>> at >>>>>> the same time and perform a configuration to avoid problems related to >>>>>> login storm. (1000 hosts) >>>>>> --> Do you think it is not a good idea? do you know what does usually >>>>>> people configure for this kind of scenarios? >>>>>> >>>>>> Thanks a lot. >>>>>> >>>>>> >>>>>> 2017-08-17 21:31 GMT+02:00 David Turner <drakonst...@gmail.com>: >>>>>> >>>>>>> If I'm understanding you correctly, you want to have 2 different >>>>>>> roots that pools can be made using. The first being entirely SSD >>>>>>> storage. >>>>>>> The second being HDD Storage with an SSD cache tier on top of it. >>>>>>> >>>>>>> https://www.sebastien-han.fr/blog/2014/08/25/ceph-mix-sata- >>>>>>> and-ssd-within-the-same-box/ >>>>>>> >>>>>>> The above guide explains how to set up the HDD root and the SSD >>>>>>> root. After that all you do is create a pool on the HDD root for RBDs, >>>>>>> a >>>>>>> pool on the SSD root for a cache tier to use with the HDD pool, and >>>>>>> then a >>>>>>> a pool on the SSD root for RBDs. There aren't actually a lot of use >>>>>>> cases >>>>>>> out there where using an SSD cache tier on top of an HDD RBD pool is >>>>>>> what >>>>>>> you really want. I would recommend testing this thoroughly and >>>>>>> comparing >>>>>>> your performance to just a standard HDD pool for RBDs without a cache >>>>>>> tier. >>>>>>> >>>>>>> On Thu, Aug 17, 2017 at 3:18 PM Oscar Segarra < >>>>>>> oscar.sega...@gmail.com> wrote: >>>>>>> >>>>>>>> Hi, >>>>>>>> >>>>>>>> Sorry guys, during theese days I'm asking a lot about how to >>>>>>>> distribute my data. >>>>>>>> >>>>>>>> I have two kinds of VM: >>>>>>>> >>>>>>>> 1.- Management VMs (linux) --> Full SSD dedicated disks >>>>>>>> 2.- Windows VM --> SSD + HHD (with tiering). >>>>>>>> >>>>>>>> I'm working on installing two clusters on the same host but I'm >>>>>>>> encountering lots of problems as named clusters look not be fully >>>>>>>> supported. >>>>>>>> >>>>>>>> In the same cluster, Is there any way to distribute my VMs as I >>>>>>>> like? >>>>>>>> >>>>>>>> Thanks a lot! >>>>>>>> >>>>>>>> Ó. >>>>>>>> _______________________________________________ >>>>>>>> ceph-users mailing list >>>>>>>> ceph-users@lists.ceph.com >>>>>>>> http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com >>>>>>>> >>>>>>> >>>>>> >>>> >>
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