156-115.77 · Question #308
The 'Maximum Entries' value in the GAiA Portal corresponds to the 'gc_thresh3' parameter in the Linux kernel and has value of 1024. Knowing this, you know that gc_thresh2 and gc_thresh1 if are…
The correct answer is B. gc_thresh2=512 and gc_thresh1=256. See the full explanation below for the reasoning.
Question
The 'Maximum Entries' value in the GAiA Portal corresponds to the 'gc_thresh3' parameter in the Linux kernel and has value of 1024. Knowing this, you know that gc_thresh2 and gc_thresh1 if are automatically set to the values:
Options
- Agc_thresh2=256 and gc_thresh1=128
- Bgc_thresh2=512 and gc_thresh1=256
- Cgc_thresh2=1024 and gc_thresh1=1024
- Dgc_thresh1=256 and gc_thresh2=128
How the community answered
(59 responses)- A7% (4)
- B73% (43)
- C3% (2)
- D17% (10)
Community Discussion
8
Luis F.Jun 26, 2026B is correct, gc_thresh2 is half of gc_thresh3 and gc_thresh1 is half of gc_thresh2, so with a Maximum Entries value of 1024 for gc_thresh3, the kernel automatically sets gc_thresh2 to 512 and gc_thresh1 to 256. That 2-to-1 ratio is the standard ARP cache threshold scaling in Linux, so once you know one value you can always derive the others.
Dervla O.Jun 26, 2026Saw this exact stem on my attempt and the only move was to recognize the halving pattern, gc_thresh3 at 1024 means thresh2 is half that at 512 and thresh1 halves again to 256, so B dropped out immediately once I read the options in order and matched the ratio. C was a trap for anyone who panicked and assumed all three shared the max value, and D was written to catch people who mixed up the numbering order, both gone in under ten seconds.
Bao N.Jun 29, 2026The numbering-order trap in D is sneakier than it looks because under pressure your eyes want to grab the first familiar number they see, so drilling that thresh1 is always the smallest, not the largest, is worth a few reps on its own before exam day.
Yusuf A.Jun 26, 2026Got this one on my actual exam last month and I almost went with A because I was thinking thirds instead of halves. Once I remembered that my senior showed me the ARP table thresholds always follow that divide-by-two pattern going down, gc_thresh3=1024 means gc_thresh2=512 and gc_thresh1=256, so B is the one.
Dervla O.Jun 28, 2026The pattern is the anchor, not the numbers themselves, because if the stem gives you any one of those three thresholds you can derive the other two and immediately eliminate any choice that breaks the halving relationship without needing to memorize a lookup table.
Brenda K.Jun 14, 2026Flag this one quick and bank the time if you are shaky on ARP internals, but if you have done any GAiA kernel tuning you should clear it in under a minute, so here is my read. GAiA sets gc_thresh1 and gc_thresh2 as proportional fractions of gc_thresh3, specifically one-eighth and one-quarter respectively, which puts gc_thresh2 at 256 and gc_thresh1 at 128 when gc_thresh3 is 1024. That quarter-and-eighth scaling is baked into how the GAiA Portal auto-derives the lower thresholds, so you are not guessing, you are applying a fixed ratio the portal enforces. A is the pick, move on.
Yusuf A.Jun 16, 2026Hey Brenda, appreciate the breakdown, but I think the ratios are actually flipped from what you said, because GAiA sets gc_thresh2 at one-half of gc_thresh3 and gc_thresh1 at one-quarter, which puts them at 512 and 256 respectively when gc_thresh3 is 1024, making B the right call here.
Bao N.Jun 26, 2026The distractor that gets people is D, which flips the variable names around, so if you memorize the formula without really internalizing the naming order you will bubble in the wrong one without even flinching. GAiA sets gc_thresh2 at half of gc_thresh3 and gc_thresh1 at half of gc_thresh2, so with 1024 as your ceiling you get 512 and 256, which is B.