Beating $3k SSD with $2k HDD?
A.K.A. Practical ZFS application on USTC Mirrors. A writeup of the talk I gave at Nanjing University this August.
Migrating Ubuntu onto ZFS
As part of a planned disk migration, I decided to move my Ubuntu installation from a traditional ext4 setup to ZFS. I did a lot of preparation and research, but things went much smoother than I had...
I almost broke our lab’s storage server…
Recently we discovered that both SSDs on our storage server were giving worrisome SMART values, so we started replacing them. One of them was used only for ZFS L2ARC, so pulling it out was easy. Th...
Request limiting in Nginx
Nginx has a built-in module limit_req for rate-limiting requests, which does a decent job, except its documentation is not known for its conciseness, plus a few questionable design choices. I happe...
Prolonging eMMC Life Span with Proxmox VE
Since my blog on installing Proxmox VE on eMMC, there’s been a lot of discussion over the Internet on this. I suspect that Proxmox decided not to include eMMCs in their hardware options by design, ...
My automated Daily Health Report infrastructure
Back in the days when the Zero COVID policy was prevailing, our university introduced a Daily Health Report system. Students and faculty were mandated to submit a daily online form detailing their ...
LVM metadata exceeds maximum metadata size, now what next?
An LVM volume group (VG) on our Proxmox VE cluster has failed to create new logical volumes, reporting that its metadata was full. At first this appears to be easy, “fine I’ll just add more space f...
Centralized Linux authentication with OpenLDAP
LDAP, the #1 way to get your graduation delayed (as has always been the meme around Tsinghua University), is every SysAdmin’s dream tool for their servers. As mighty as its rumors fly, LDAP takes t...