How to replace drive in my DS115J

All, Hello - just joined. I could not find a YouTube video on this and I am very new to the NAS world. I currently have a DS115J with a 6TB drive that is at least 95% full and I want to updgrade to an 8TB (I plan on replacing the 115J with a DS923+ when I have saved up enough money). Is there a simple way to do this? I want to only buy the 8TB andthought I could perhaps clone the drive? Any help will be very much appreciated.

Tell us more about any application you might use, whether it is for file management only, and whether you have a complete backup.

I do not have a backup (the NAS has the largest of my hard drives. I’m using DSM 6.2 on the synology DS115J. All I want to do is remove the 6TB drive and install an 8TB drive but not lose the informaiotn on the 6TB. It is a home use only NAS>

No backup? That’s risky. In fact, you risk all.

To replace the drive requires backing up all content (apps, files) to an external destination (ex. USB drive, second NAS, cloud service) using Hyper Backup. Once that is complete. Swap drives (powered off) and install Hyper Backup. Select Restore, and link to your external backup.

Two comments … An 8 TB drive offers little additional relief. I would use at least a 12 TB replacement drive.

Re: DS923+ … You cannot migrate drives from single drive NAS models to multidrive units, so again, an external backup is helpful here.

A single disk NAS and no backup. Not sure what you data is worth to you.
That said, a low cost migration scenario for this type of NAS is that you buy a SATA to USB connector.
You swap disks and set up the new disk. Connect the old disk to the USB port with the connector and copy over all data.
To further streamline the process, you can make a configuration backup to your computer of the current setup and restore that backup to the renewed system. This backup type is very small and contains users, groups, shared folders and permissions.