{"id":626,"date":"2026-01-26T21:05:02","date_gmt":"2026-01-26T20:05:02","guid":{"rendered":"https:\/\/www.familie-kleinman.nl\/brain\/?p=626"},"modified":"2026-01-26T21:05:02","modified_gmt":"2026-01-26T20:05:02","slug":"hindsight-and-proxmox-mistakes-were-made","status":"publish","type":"post","link":"https:\/\/www.familie-kleinman.nl\/brain\/index.php\/2026\/01\/26\/hindsight-and-proxmox-mistakes-were-made\/","title":{"rendered":"Hindsight and Proxmox: mistakes were made"},"content":{"rendered":"

Yeah, my Proxmox cluster hasn\u2019t even been fully operational for 48 hours yet, and I\u2019m already writing an article titled “Mistakes Were Made.”<\/p>\n

I genuinely wish I had known some of this beforehand, because it would have saved me time and, quite possibly, money.<\/p>\n

Storage<\/h2>\n

I am already running out of storage. Yes. Not even 48 hours in, and I am actually running out of storage. HA storage, to be exact.<\/p>\n

\"\"<\/p>\n

“But you\u2019re only at 50%! There\u2019s loads of room!”<\/p><\/blockquote>\n

Yeah. No.<\/p>\n

I still have a huge VM left to migrate. That VM has a data disk of just over 1 TB. And because this is Ceph with replication enabled, that single terabyte does not consume 1 TB of storage. It consumes roughly 3 TB.<\/p>\n

As the screenshot shows, that one remaining migration alone would push the cluster straight into uncomfortable territory.<\/p>\n

“But then the drive would still have about 20% free space. That\u2019s huge!”<\/p><\/blockquote>\n

On a regular disk, sure.<\/p>\n

On a Ceph cluster, absolutely not. Twenty percent free space is not breathing room; it is a warning sign. Ceph needs headroom to rebalance data, recover from failures, and generally keep itself healthy. Once you get close to that range, things stop being comfortable very quickly.<\/p>\n

So yeah. I made one fairly big mistake here.<\/p>\n

I genuinely thought I had more than enough headroom with 6×1.92 TB. On paper it looked fine. In reality, once replication, HA requirements, and one large remaining VM entered the picture, that headroom evaporated much faster than expected.<\/p>\n

Now what?<\/h3>\n

First, let\u2019s get the obvious joke out of the way.<\/p>\n

Kioxia, Samsung, or any other enterprise SSD manufacturer: you could really lend me a hand here.<\/p>\n

But more seriously, I really only have a few options:<\/p>\n

    \n
  1. Accept that my Nextcloud instance won\u2019t be running on my HA platform anytime soon.<\/li>\n
  2. Buy 3x 1.92 TB drives and add them to the Ceph cluster, effectively increasing usable capacity by roughly 1.92 TB.<\/li>\n
  3. Buy 3x 3.84 TB drives and add them to the Ceph cluster, effectively increasing usable capacity by roughly 3.84 TB.<\/li>\n<\/ol>\n

    And that is about it.<\/p>\n

    And adding three more drives introduces yet another problem.<\/p>\n

    Both NOX cases are already full. There is simply no room left for an additional drive.<\/p>\n

    Which means there\u2019s only one conclusion left: another case it is.<\/p>\n

    How am I going to fix this rather fundamental issue?<\/p>\n

    Not by rushing it, that\u2019s for sure.<\/p>\n

    Brain out<\/p>\n

     <\/p>\n

     <\/p>\n

     <\/p>\n","protected":false},"excerpt":{"rendered":"

    Yeah, my Proxmox cluster hasn\u2019t even been fully operational for 48 hours yet, and I\u2019m already writing an article titled “Mistakes Were Made.” I genuinely wish I had known some of this beforehand, because it would have saved me time and, quite possibly, money. Storage I am already running out of storage. Yes. Not even…<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[324],"tags":[400,311,399,401,247,312],"class_list":["post-626","post","type-post","status-publish","format-standard","hentry","category-proxmox","tag-booboo","tag-ceph","tag-fuckup","tag-mistake","tag-proxmox","tag-storage"],"yoast_head":"\nHindsight and Proxmox: mistakes were made - Brain's Ramblings<\/title>\n<meta name=\"description\" content=\"Building a Proxmox HA cluster with Ceph sounded straightforward, until storage reality hit. 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