My Plex Server Is Running Out of Storage: How Do I Expand It?
As an Amazon Associate we earn from qualifying purchases. Prices and availability come from Amazon.com as of the last update and may change.
First find out which drive is full: the one with your media, or the one with the Plex Media Server data directory. If it is the data directory, nothing needs buying at first, because video preview thumbnails are one of the most common reasons it grows and Plex lets you delete them. If the media drive is full, Plex names three paths: a larger hard drive, a NAS, or another new location. You can also add a folder on a new drive to the library you already have.
Check your situation
Work it out for your hardware
Synology DS923+: 4 bays, drives up to 24TB each, from Synology DS923+ datasheet. Drive compatibility for this model.
Path 1: swap drives one at a time
Space first rises at swap 2. The swaps before it gain nothing you can use. Each swap is one rebuild of a 8TB array member: 11.1 hours at 200MB a second, 22.2 hours at 100MB a second.
| Drives swapped | Usable space | Gained | Rebuild time so far |
|---|---|---|---|
| 1 of 4 | 24TB | nothing yet | 11.1 hours to 22.2 hours |
| 2 of 4 | 32TB | +8TB | 22.2 hours to 44.4 hours |
| 3 of 4 | 40TB | +16TB | 33.3 hours to 2.8 days |
| 4 of 4 | 48TB | +24TB | 44.4 hours to 3.7 days |
The two rates are yours: read them from your NAS during a rebuild or a scrub. A system that rebuilds only the used space finishes sooner. The last step, expanding onto the new space, takes extra time this tool cannot estimate.
- Synology supports replacing drives to expand SHR, SHR-2, RAID 1, RAID 5, RAID 6, RAID 10 and RAID F1 pools.
- Replace the smallest drive first. When every drive is the same size, at least two have to be replaced with larger ones before the pool can grow.
Path 2: add drives to empty bays
All 4 bays are in use, so there is nowhere to add a drive.
Path 3: back up, start again with 4 x 16TB
A new array of 4 x 16TB in SHR (Synology Hybrid RAID) holds 48TB, the same as the end of path 1, reached in one build instead of 4 rebuilds. It needs a complete copy of your data somewhere else first, because creating the new array erases the drives. At today's cheapest 16TB drive, 4 drives cost $2,357.80.
16TB drives that fit, by price
New 3.5-inch SATA drives rated for NAS or enterprise use whose maker confirms CMR recording, no larger than this model's 24TB per-bay limit. Prices are live from Amazon.com. As an Amazon Associate the site earns from qualifying purchases.
The rules this tool applies, with their sources, are on its own page: NAS Upgrade Advisor.
Safe steps
- Back up your Plex Media Server data before you make major changes to a library.[1]
- Keep that backup outside the Plex data folder. The server may delete files it does not know when it clears out unused files.[8]
- On Windows and Linux you can leave the Cache directory out of the backup to save space and time.[8]
What to buy, if anything
Answer the questions under "Check your situation" and this section narrows to what your case calls for. Until then every table is shown, each with the case it is for.
Larger drives for the Plex media library
Why this is here: The media itself has outgrown its drive or array, so a larger drive (or larger NAS drives) is the purchase; these are the candidates for the new media location or for the NAS swap the advisor plans. New 3.5-inch SATA NAS and enterprise hard drives of 12 TB and up whose maker confirms CMR recording, with today's Amazon.com price per TB.
Sources
- Plex Support: Move Media Content to a New Location checked 2026-10-14
- Plex Support: Why is my Plex Media Server directory so large? checked 2026-10-14
- Plex Support: Where is the Plex Media Server data directory located? checked 2026-10-14
- Plex Support: Video Preview Thumbnails checked 2026-10-14
- Plex Support: Transcoder (server settings) checked 2026-10-14
- Plex Support: Editing Libraries checked 2026-10-14
- Plex Support: Creating Libraries checked 2026-10-14
- Plex Support: Backing Up Plex Media Server Data checked 2026-10-14
Facts on this page were reviewed on October 14, 2026. Prices and stock are from Amazon.com as of October 14, 2026.