Hi Steven,
Just to somewhat clarify my previous post, I mention OSDs in the sense that the OS is installed on the OSD server using the SD card, I would absolutely recommend against using SD cards as the actual OSD media. This of course misses another point, which is for the Mons or other such services, I would also strongly advise against an SD card setup much more explicitly due to the mon’s store.db, which during tunables being altered can grow dramatically and incur excessive wear on an SD card rapidly. Kind Regards, Tom From: ceph-users <ceph-users-boun...@lists.ceph.com> On Behalf Of tho...@thomaswhite.se Sent: 13 August 2018 20:27 To: 'Steven Vacaroaia' <ste...@gmail.com>; 'ceph-users' <ceph-users@lists.ceph.com> Subject: Re: [ceph-users] limited disk slots - should I ran OS on SD card ? Hi Steven, If you are running OSDs on the SD card, there would be nothing technically stopping this setup, but the main factors against would be the simple endurance and performance of SD cards and the potential fallout when they inevitably fail. If you factor time and maintenance as a cost just as much as the hardware, you would be far better off getting a small NVME drive as mentioned. With regarding to booting from the NVME, I don’t know the answer to that unfortunately as we don’t use R620’s (our preference is the Dell 730XD), but I’ll check with some of our DC to see if they have that info to hand and let you know. In my view, keep OS activity entirely separate from OSD operations too. Mixing the two can introduce a host of other problems which will cause a lot of pain along the way, such as receiving a hanging messages from the kernel trying to perform OS writes if the osd process is in a full recovery state. Always account for your failure redundancy in the worst case scenario and not the ideal one, I found this out personally on a very large cluster and is not a fun experience. Kind Regards, Tom From: ceph-users <ceph-users-boun...@lists.ceph.com <mailto:ceph-users-boun...@lists.ceph.com> > On Behalf Of Steven Vacaroaia Sent: 13 August 2018 19:53 To: ceph-users <ceph-users@lists.ceph.com <mailto:ceph-users@lists.ceph.com> > Subject: [ceph-users] limited disk slots - should I ran OS on SD card ? Hi, I am in the process of deploying CEPPH mimic on a few DELL R620/630 servers These servers have only 8 disk slots and the larger disk they accept is 2 TB Should I share a SSD drive between OS and WAL/DB or ran OS on internal SD cards and dedicated SSD to DB/WAL only ? Another option is to use NVME ( can still get DC P3700) but not sure if DELL R620 allows booting from it Any advice would be greatly appreciated I am still waiting for budget approval to buy disks In my small test environment I did not notice any performance hit when OS was on SD card Many thanks Steven
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