​The biggest issue i have is that i am working with a mac mini. the 1T drive is a 5400 rpm drive. this has been my home server for a while running server 2016, but it is time to put something more useful on it. Part of this is specifically to learn how to use lvm and lvmcache.​ And ram is on the list for this server just not in the budget yet. I am not worried about catastrophic failure or the like as nothing lives on this server that does not already live anywhere else. I did the install with the Ubuntu server install so i could at least get lvm set up partly ahead of time. so it looks like I am in a good place. I was reading that article as i received your email. So now to extend the vg create the cache and meta lv's and turn things on. lvm> pvscan PV /dev/sdb2 VG System lvm2 [922.20 GiB / 0 free] PV /dev/sda3 lvm2 [117.38 GiB] Total: 2 [1.02 TiB] / in use: 1 [922.20 GiB] / in no VG: 1 [117.38 GiB] lvm> pvs PV VG Fmt Attr PSize PFree /dev/sda3 lvm2 --- 117.38g 117.38g /dev/sdb2 System lvm2 a-- 922.20g 0 lvm> vgs VG #PV #LV #SN Attr VSize VFree System 1 1 0 wz--n- 922.20g 0 lvm> vgdisplay --- Volume group --- VG Name System System ID Format lvm2 Metadata Areas 1 Metadata Sequence No 2 VG Access read/write VG Status resizable MAX LV 0 Cur LV 1 Open LV 1 Max PV 0 Cur PV 1 Act PV 1 VG Size 922.20 GiB PE Size 4.00 MiB Total PE 236082 Alloc PE / Size 236082 / 922.20 GiB Free PE / Size 0 / 0 On Fri, Jul 8, 2016 at 11:02 AM, Matt Graham wrote: > On 2016-07-08 10:00, Stephen Partington wrote: > >> 1T spinning disk and 128G SSD installed. [...] going with LVM-Cache >> Sadly the Ubuntu server installation does not have the option of >> setting up LVM for anything other than its most basic configuration >> > > LVM is complicated, and using LVM-cache is a bit more complicated than > just making some PVs and putting them into a VG and then making LVs. > > What I understand about LVM is that you can build your LVM group and >> then migrate/expand it without a full install/wipe or 3rd disk device >> to host your core os installation. Can this be done for LVM cache as >> well? >> > > Yes. Your setup would be something like this: 2 PVs, one on the fast > disk, one on the slow disk[0]. One VG with both PVs in it. Multiple LVs. > One named root on the fast disk (mounted at / obviously), one small one > named cache-meta on the fast disk, one larger one named cache on the fast > disk, and finally one larger one named origin on the slow disk. You'd > probably mount the last one on /data or /home or wherever makes sense to > put the large amount of stuff you want to serve up. I suppose you could > put / on the spinny-disk and use almost all of the SSD for cache too. Your > call. > > If you already have some PVs and LVs set up, you might need to use pvmove > and lvresize and resize2fs to resize filesystems and LVs and move them to > the appropriate PV. These things are of course doable from a running > system and should not cause any problems. > > https://rwmj.wordpress.com/2014/05/22/using-lvms-new-cache-feature/ > describes all the commands you'd need to run to make this stuff happen. > And getting an additional 4G or 8G of RAM might help more than using an SSD > as a cache, depending on what exactly is going on. > > (I haven't actually tried this, but I've got a 32G unused partition on my > SSD right now, and this could be a fun weekend project. I will let you > know if I run into any problems.) > > [0] With 1T disks as cheap as they are, consider a softRAID-1 instead of a > single spinny disk. Disk failures are No Fun At All. > > -- > Crow202 Blog: http://crow202.org/wordpress > There is no Darkness in Eternity > But only Light too dim for us to see. > --------------------------------------------------- > PLUG-discuss mailing list - PLUG-discuss@lists.phxlinux.org > To subscribe, unsubscribe, or to change your mail settings: > http://lists.phxlinux.org/mailman/listinfo/plug-discuss > -- A mouse trap, placed on top of your alarm clock, will prevent you from rolling over and going back to sleep after you hit the snooze button. Stephen