Hi, Yes, you are right, the idea is cloning a snapshot taken from the base image...
And yes, I'm working with the current RC of luminous. In this scenario: base image (raw format) + snapshot + snapshot clones (for end user Windows 10 vdi). Does tiering ssd+hdd may help? Thanks a lot El 18 ago. 2017 4:05, "David Turner" <drakonst...@gmail.com> escribió: Do you mean a lot of snapshots or creating a lot of clones from a snapshot? I can agree to the pain of crating a lot of snapshots of rbds in ceph. I'm assuming that you mean to say that you will have a template rbd with a version snapshot that you clone each time you need to let someone log in. Is that what you're planning? On Thu, Aug 17, 2017, 9:51 PM Christian Balzer <ch...@gol.com> wrote: > > Hello, > > On Fri, 18 Aug 2017 03:31:56 +0200 Oscar Segarra wrote: > > > Hi Christian, > > > > Thanks a lot for helping... > > > > Have you read: > > http://docs.ceph.com/docs/master/rbd/rbd-openstack/ > > > > So just from the perspective of qcow2, you seem to be doomed. > > --> Sorry, I've talking about RAW + QCOW2 when I meant RBD images and RBD > > snapshots... > > > I tested Snapshots with Hammer and the release before it, found them > immensely painful (resource intensive) and avoided them since. > That said, there are supposedly quite some improvements in recent versions > (I suppose you'll deploy with Luminous), as well as more (and > working) control knobs to reduce the impact of snapshot operations. > > > A sufficiently large cache tier should help there immensely and the base > image > > should be in cache (RAM, pagecache on the OSD servers really) all the > time > > anyway. > > --> If talking about RBD images and RBD snapshots... it helps immensely > as > > well? > > > No experience, so nothing conclusive and authoritative from my end. > If the VMs write/read alot of the same data (as in 4MB RBD objects), > cache-tiering should help again. > But promoting and demoting things through it when dealing with snapshots > and deletions of them might be a pain. > > Christian > > > Sizing this and specifying the correct type of SSDs/NVMes for the > cache-tier > > is something that only you can answer based on existing data or > sufficiently > > detailed and realistic tests. > > --> Yes, the problem is that I have to buy a HW and for Windows 10 VDI... > > and I cannot make realistic tests previously :( but I will work on this > > line... > > > > Thanks a lot again! > > > > > > > > 2017-08-18 3:14 GMT+02:00 Christian Balzer <ch...@gol.com>: > > > > > > > > Hello, > > > > > > On Thu, 17 Aug 2017 23:56:49 +0200 Oscar Segarra 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) > > > > > > > Have you read: > > > http://docs.ceph.com/docs/master/rbd/rbd-openstack/ > > > > > > So just from the perspective of qcow2, you seem to be doomed. > > > > > > Windows always appears to be very chatty when it comes to I/O and also > > > paging/swapping seemingly w/o need, rhyme or reason. > > > A sufficiently large cache tier should help there immensely and the > base > > > image should be in cache (RAM, pagecache on the OSD servers really) > all the > > > time anyway. > > > Sizing this and specifying the correct type of SSDs/NVMes for the > > > cache-tier is something that only you can answer based on existing > data or > > > sufficiently detailed and realistic tests. > > > > > > Christian > > > > > > > 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 > > > > >>>> > > > > >>> > > > > >> > > > > > > > > > -- > > > Christian Balzer Network/Systems Engineer > > > ch...@gol.com Rakuten Communications > > > > > > -- > Christian Balzer Network/Systems Engineer > ch...@gol.com Rakuten Communications >
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