Just in case anyone in future comes up with the same question: I ran the following Test-case: 3 identical Debian VM's. 4GB Ram, 4 vCores. Virtio for vDisks. On the same Pool. vDisks mounted at /home/test 1x 120GB 12x 10GB JBOD via LVM 12x 10GB Raid 0 Then separately i wrote 100GB of Data using dd onto /home/test/testfile. All 3 Benchmarks had statistically the same write speeds. However the CPU-Consumption was about 5% higher on LVM and about 35% when using mdadm Raid-0 for 12 vDisks. Question: Does Ceph have a upper limit for how "BIG" i can make virtio based vDisks on a EC-Pool ? ----- Original Message ----- > From: "Wolf F." <wolf.f@xxxxxxxxxxxx> > To: ceph-users@xxxxxxxxxxxxxx > Sent: Saturday, January 2, 2016 9:21:46 PM > Subject: krdb vDisk best practice ? > Running a single node Proxmox "cluster", with Ceph on top. 1 Mon. Same node. > I have 24 HDD (no dedicated journal) and 8 SSD split via "custom crush location > hook". > Cache-Tier (SSD-OSD) for a EC-pool (HDD-OSD) providing access for proxmox via > krdb. > 15 TB Capacity (Assortment of Disk sizes/speeds). Vdisks are Virtio and XFS. > OSD's are XFS as well. > > While setting up a virtual OpenmediaVault (VM) the following Question arose > regarding vDisks (virtio) and their best practice. > > > Q1: How does the amount and size of vDisks affect Write/Read performance? Do i > bottleneck myself with overhead (single Mon)? Or does it maybe not matter at > all? > > Values are academic examples. > 120x 100GB vDisks - In OMV as Raid0 > 120x 100GB vDisks - In OMV as JBOD > > 12x 1TB vDisk - In OMV as Raid0 > 12x 1TB vDisk - In OMV as JBOD > > 2x 6TB vDisk - In OMV as Raid0 > 2x 6TB vDisk - In OMV as JBOD > > Q2: How does this best practice change if i add 2 more nodes (same config) and > by implication 2 more mons? > > > Not been able to find much on this topic. > > kind regards, > Wolf F. _______________________________________________ ceph-users mailing list ceph-users@xxxxxxxxxxxxxx http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com
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