On Thu, Feb 2, 2017 at 12:09 PM, Yaniv Kaul <yk...@redhat.com> wrote:
> > > >> >> I decided to switch to preallocated for further tests and confirm >> So I created a snapshot and then a clone of the VM, changing allocation >> policy of the disk to preallocated. >> So far so good. >> >> Feb 2, 2017 10:40:23 AM VM ol65preallocated creation has been completed. >> Feb 2, 2017 10:24:15 AM VM ol65preallocated creation was initiated by >> admin@internal-authz. >> Feb 2, 2017 10:22:31 AM Snapshot 'for cloning' creation for VM 'ol65' has >> been completed. >> Feb 2, 2017 10:22:31 AM Snapshot 'for cloning' creation for VM 'ol65' was >> initiated by admin@internal-authz. >> >> so the throughput seems ok based on this storage type (the LUNs are on >> RAID5 made with sata disks): 16 minutes to write 90Gb is about 96MBytes/s, >> what expected >> > > What is your expectation? Is it FC, iSCSI? How many paths? What is the IO > scheduler in the VM? Is it using virtio-blk or virtio-SCSI? > Y. > > Peak bandwith no more than 140 MBytes/s, based on storage capabilities, but I don't have to do a rude performance test. I need stability Hosts has a mezzanine dual-port HBA (4 Gbit); each HBA connected to a different FC-switch and the multipath connection has 2 active paths (one for each HBA). I confirm that with preallocated disk of the cloned VM I don't have indeed the previous problems. The same loop executed for about 66 times in a 10 minutes interval without any problem registered on hosts No message at all in /var/log/messages of both hosts. My storage domain not compromised It remains important the question about thin provisioning and SAN LUNs (aka with LVM based disks). In my opinion I shouldn't care of the kind of I/O made inside a VM and anyway it shouldn't interfere with my storage domain, bringing down completely my hosts/VMs. In theory there could be an application inside a VM that generates something similar to my loop and so would generate problems. For sure I can then notify VM responsible about his/her workload, but it should not compromise my virtual infrastructure I could have an RDBMS inside a VM and a user that creates a big datafile and that should imply many extend operations if the disk is thin provisioned.... What about [irs] values? Where are they located, in vdsm.conf? What are defaults for volume_utilization_percent and volume_utilization_chunk_mb? Did they change from 3.6 to 4.0 to 4.1? What I should do after changing them to make them active? Thanks in advance, Gianluca
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