Slow backup jobs
When a client's backup job runs slower than expected, work through these checks in order. They start with the most common causes.
First: narrow it down
- Is it one device or many? If jobs are slow across multiple clients, look at what they share (the storage destination or the internet connection) rather than the individual machine.
- Did it start suddenly? Check for recently installed software on the device (Windows: Programs and Features, sort by install date) and whether the slowdown coincides with a Magnus Box software update or a new Storage Vault.
Device-side causes
Antivirus scanning. Many AV products scan every file as Magnus Box reads it (ESET NOD32 and Windows Defender among them). Magnus Box automatically registers a Windows Defender exclusion for its backup-tool.exe process. For other AV products, add an exclusion manually and test again. During a job, check whether the AV process shows high usage in Task Manager.
Slow settings turned on. In the Protected Item and schedule settings, check that:
- "Limit backup to use only 1 disk thread" is off
- No speed limit is set
- "Prefer temporary files instead of RAM (slower)" is off
- You've tried "Rescan unchanged files" both on and off. It can help or hurt, depending on the data.
RAM pressure. Multi-TB Storage Vaults require several GB of RAM for deduplication indexes. If the device is low on RAM, it starts using the page file, which slows everything down badly. Consider splitting very large vaults per device. See Out of memory.
CPU bottleneck. All data is compressed and encrypted on the device before upload. On low-powered CPUs this can be the limiting factor.
Storage-side causes
Backing up from a network share. Every file needs several trips across the network. Installing the backup app on the device that holds the data is usually much faster.
Source and destination on the same spinning disk. A mechanical drive doing both jobs at once drops from sequential to random-access performance.
Single-queue source disks. Magnus Box reads the source disk with many parallel requests at low OS priority. On disks that only support a single queue, try turning on "Limit backup to use only 1 disk thread". This can help other programs on the machine, but backups will be slower.
External USB drives.
- Confirm USB 3 rather than USB 2.
- Test the drive on its own (for example with CrystalDiskMark) for sequential and small random reads, to get a baseline.
- The Windows "Quick removal" policy slows USB drives down. To change it, go to Device Manager > Disk drives > [drive] > Properties > Policies, select Better performance and turn on write caching. The drive must then be safely ejected before you unplug it.
Backing up direct to cloud storage. Check the client's internet connection and the storage provider's status page.
If that doesn't fix it
Open the job log from a slow run (in the Web Portal: Job logs, or the user's Job Logs tab) and note which part is slow: scanning, uploading or finishing. Then email support@magnusbox.com with the user name, device name and the job log.