Lab 13 · Compatibility

The next-day backup on the same 6 accounts: 494 s on JetBackup, 64 s on Salvo

Date: Oct 16, 2026Server: production cPanel, 6 WordPress accountsReading time: 3 minTopic: Compatibility

The question

The nightly backup is what weighs most over a year: it runs 365 times, sharing the server with the sites and the storage with the other servers. Day to day, the incremental backup each night, how long does each take on the same accounts, on the same server?

Result

7.7×less total time on Salvo: 64 s versus 494 s, on the same 6 accounts (3.3× to 11× per account)

37 to 61files read per account on Salvo, out of 13 to 34 thousand; only 5 to 28 were site and email files, the rest are the account configuration and dumps

Why it matters to whoever runs the server

64 s versus 494 s on the same 6 accounts: a backup window 7.7× shorter, with the differences in conditions the post shows.
Out of 13 to 34 thousand files per account, only 37 to 61 were read: the server barely reads what didn’t change.

Time per account on the next-day backupIn seconds · different conditions, see the caveats · * Salvo only: JetBackup’s log doesn’t record files or MB; “read” includes the account configuration and dumps

Source: JetBackup 5.4.1.4 log and Salvo Lab · production cPanel server · Oct 16, 2026

Account	JetBackup	Salvo	Files	Size	Read*	Processed*	Written*
A	74 s	9.9 s	23,220	633.7 MB	37	15.3 MB	0.4 MB
B	150 s	13.6 s	28,772	737.5 MB	61	77.0 MB	5.5 MB
C	33 s	10.1 s	13,224	986.4 MB	37	50.1 MB	0.6 MB
D	66 s	8.6 s	20,666	454.5 MB	40	8.4 MB	0.2 MB
E	93 s	11.7 s	34,302	694.9 MB	44	28.7 MB	1.0 MB
F	78 s	10.1 s	22,275	739.2 MB	61	43.1 MB	5.7 MB
Total	494 s	64.0 s	142,459	4,246.3 MB	280	222.7 MB	13.5 MB

Method

A production cPanel server, 6 WordPress accounts of about 1 GB each (13 to 34 thousand files). Full account on both: configuration, files, email and databases.

JetBackup 5.4.1.4: the server’s normal nightly backup, with 5 accounts at once. Times were read from its log.

Salvo: the next-day backup (about 12 h after the previous one), in the morning, with 3 accounts at once and low priority. The 6 accounts finished in 24 s of wall-clock time.

Why the difference: on JetBackup, 75% to 90% of each account’s time is the transfer; rsync checks every file against the previous copy on the storage and creates a hardlink for each unchanged file. Salvo checks on the server itself, using the previous backup’s file list, skips what didn’t change without reading it, and sends only what’s new to the storage.

What we decided

Nothing changes in Salvo. This is the first time comparison on the same accounts, and the conditions weren’t the same (see below).

What we don’t know yetThe times of day were different: JetBackup ran before dawn, with the server quiet; Salvo, in the morning, with the sites active. JetBackup had read the files about 4 h earlier, and part of them may have been in system memory. It was 5 accounts at once on JetBackup and 3 on Salvo. And these are six accounts on one server, not a market average; JetBackup used an SSH destination.

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How it connects to the other labs

Faster backups

30 MB30 MB of cache for 233 thousand files, and deleting it cost nothingLab 01 · Oct 14, 2026 3×The limit was the encryption, not the network: switching ciphers tripled the uploadLab 06 · Oct 15, 2026 8 msCompression is the costliest step of the backup; encryption barely registersLab 07 · Oct 15, 2026 141The engine uploads 141 MB/s reading one file per core; 4 accounts together used 2.4 GB of memoryLab 08 · Oct 15, 2026 33 s3 full cPanel accounts in 33 s on a production server; the incremental, in 7 sLab 09 · Oct 15, 2026 4 sThe next-day backup, before dawn and cold: 4 s for 21 thousand filesLab 12 · Oct 16, 2026 166×The first backup side by side: 45% less time and 166× fewer files on the storageLab 14 · Oct 16, 2026 99.98%WordPress backup with email: 6 real sites restored by Salvo and by JetBackupLab 23 · Oct 19, 2026