Je, unajuaje kama kizuizi ni CPU, kumbukumbu, I/O, au mtandao?

Question

Accepted Answer

**Angalia matumizi ya rasilimali na kubanika, kisha hakiki kwa kupima.** Njia ya utaratibu — **USE method** (Utilization, Saturation, Errors) — angalia kila rasilimali ili usizini lajumu lisilo sahihi.

## USE method

Kwa kila rasilimali (CPU, kumbukumbu, disk, mtandao), uliza maswali matatu:

```text
UTILIZATION → how busy is it (% time in use)?
SATURATION  → how much queued/waiting work (load, run queue, swap)?
ERRORS      → any errors (dropped packets, disk errors, OOM kills)?
→ a resource that is saturated, not just busy, is usually the bottleneck.
```

## Zana na dalili kwa kila rasilimali

Kila rasilimali ina saini tofauti unayoweza kusoma kwa zana za kawaida:

```text
CPU     → top/htop: high %us or load > #cores, run queue backed up
MEMORY  → free/vmstat: low free RAM + high SWAP in/out (si/so) → swapping = thrashing
DISK I/O→ iostat/vmstat: high %iowait, %util ~100%, high await → I/O-bound
NETWORK → iftop/sar/ss: bandwidth saturated, retransmits, high latency
```

Tofauti muhimu: **mzigo mrefu na %us juu** inamaanisha imeambatana na CPU; **kubadilishana (si/so)** inamaanisha shinikizo la kumbukumbu; **%iowait juu** inamaanisha CPU haipo *inakusubiri disk*; **latency/retransmits** juu inaonyesha mtandao.

```text
$ vmstat 1
 r  b   swpd  free   si  so   bi   bo  us sy id wa
 8  0      0  120m   0   0   12   20  92  6  2  0   ← CPU-bound (id=0, wa=0)
 1  3 800m   30m  40 120  900    8   5  3  2 90   ← I/O + swap (wa=90, so>0)
```

## Hakiki kwa kupima

Usisimame kwenye nambari moja. **Profili** mchakato (kwa mfano `perf`, CPU/heap profiler) kupata kazi ya moto au mkakati, badilisha kitu kimoja na **pima tena**. Dalili zinaweza kukozesha — CPU juu inaweza kuwa foleni isiyo na kazi inayosababishwa na mgogoro wa kufuli, sio kazi halisi.

## Kwa nini ni muhimu

Kurekebisha rasilimali isiyosahihi (kuongeza RAM kwenye sanduku lililoambatana na CPU) hubazifu pesa wala hausaidia. USE method pamoja na zana sahihi inatenga kizuizi halisi haraka, na kupima tena kunathibitisha kwamba takriban ilibadilisha sindano.