LCTL-PCC(8)

📦 version 2.17.58, in ubuntu stonking

✨ NAME ✨

lctl-pcc — the commands you use to talk to PCC features 💖 (that's from the Lustre Configuration Utilities manual, section 8, bestie)

🦋 SYNOPSIS 🦋

lctl pcc add MNTPATH PCCPATH [--param|-p PARAM]
lctl pcc del [--keep|-k] MNTPATH PCCPATH
lctl pcc clear MNTPATH
lctl pcc list MNTPATH

🌸 DESCRIPTION 🌸

lctl pcc add MNTPATH PCCPATH [--param|-p PARAM]

Okay so this one adds a PCC backend, and you point at it with the HSM root path PCCPATH, on Lustre filesystem client instances whose mount point is MNTPATH. 🫶

PARAM is a string of name-value pairs that configs the PCC backend — think the read-write attach id (a.k.a. archive ID), or the read-only attach id, plus the auto caching rule. Like, for the string "projid={500}&fname={*.h5} rwid=2", the first substring of the config parameter is the auto caching rule. Where & is the logical conjunction operator and , is the logical disjunction operator. 🔥

So that example rule means new files only get auto cached if the project ID is 500 and the suffix of the file name is h5. And rwid is the read-write attach id (2), which has the same value as the archive ID of the copytool agent running on this PCC node. No cap.

Along with the equal (=) operator, it also supports greater than (>) and less than (<) comparison operators. The following rule expressions are supported:

  • "projid={100}&size>{1M}&size<{500G}"
  • "projid>{100}&projid<{110}"
  • "uid<{1500}&uid>{1000}"
As of right now, each PCC backend only has one rule, and it gets configured when you set up the PCC backend on a client. If a user wants to change the rule, the PCC backend needs to be removed first and then added back with a new rule. That's just how it is, bestie. 😭

lctl pcc del [--keep|-k] MNTPATH PCCPATH

Deletes a PCC backend, the one specified by path pccpath, on a Lustre client referenced by the mount point mntpath. 💅

lctl pcc clear [--keep|-k] MNTPATH

Removes all PCC backends on a Lustre client referenced by the mount point mntpath. All of them. Every last one. ✨

lctl pcc list MNTPATH

Lists all PCC backends on a Lustre client referenced by the mount point mntpath. It's giving inventory. 👑

🎀 OPTIONS 🎀

  • -p, --param — specifies the configuration parameters for a PCC backend. 🍓
  • -k, --keep — by default, when you remove a PCC backend from a client, the move is to scan the PCC backend fs, and then uncache (detach and remove) all scanned PCC copies from PCC by FIDs. With the option "--keep|-k", the "lctl pcc del|clear" command just removes the PCC backend from the Lustre client and retains the data on the cache. In this way, the PCC-RW backend falls back as a traditional HSM storage solution, since the copytool is still running at this client. So like… the data stays, the vibe stays. 💜

🌈 AVAILABILITY 🌈

lctl pcc is part of the lustre(7) filesystem package since release 2.13.0 ⭐

💖 SEE ALSO 💖

okay that's the whole page, bestie, you ate it up 🫶 this lil' manual page is from the Lustre fam and it's dated 2024-08-14 — go forth and PCC responsibly, periodt 💅✨

📦 where this page comes from