diff --git a/docs.it4i/barbora/storage.md b/docs.it4i/barbora/storage.md
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--- a/docs.it4i/barbora/storage.md
+++ b/docs.it4i/barbora/storage.md
@@ -149,7 +149,8 @@ The SCRATCH filesystem is realized as Lustre parallel filesystem and is availabl
### PROJECT File System
-TBD
+The PROJECT data storage is a central storage for projects'/users' data on IT4Innovations that is accessible from all clusters.
+For more information, see the [PROJECT storage][6] section.
### Disk Usage and Quota Commands
@@ -353,6 +354,7 @@ Transfer rates of about 28 MB/s can be expected.
[3]: #cesnet-data-storage
[4]: ../general/obtaining-login-credentials/obtaining-login-credentials.md
[5]: #project-file-system
+[6]: ../storage/project-storage.md
[a]: http://www.nas.nasa.gov
[b]: http://www.nas.nasa.gov/hecc/support/kb/Lustre_Basics_224.html#striping
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@@ -0,0 +1,144 @@
+# PROJECT Data Storage
+
+The PROJECT data storage is a central storage for projects'/users' data on IT4Innovations.
+The PROJECT data storage is accessible from all IT4Innovations clusters, it allows to share data amongst clusters.
+The storage is intended to be used throughout the whole project's lifecycle.
+
+## Technical Overview
+
+The PROJECT storage consists of three equal file storages (blocks) called PROJ1, PROJ2, and PROJ3.
+Each file storage implements GPFS file system exported via NFS protocol using three NFS servers.
+File storages provide high-availability and redundancy.
+
+
+
+| Specification | Total | Per Block |
+| ----------------- | -------------------|-------------------- |
+| Protocol | NFS over GPFS |
+| Total capacity | 15PB | 5PB |
+| Throughput | 39GB/s | 13GB/s |
+| IO Performance | 57kIOPS | 19kIOPS |
+
+## Accessing PROJECT
+
+All aspects of allocation, provisioning, accessing, and using the PROJECT storage are driven by project paradigm.
+Storage allocation and access to the storage are based on projects (i.e. computing resources allocations) and project membership.
+
+A project directory (actually implemented as an independent fileset) is created for every active project.
+Default limits (quotas), default file permissions, and ACLs are set.
+The project directory life cycle strictly follows the project's life cycle.
+The project directory is removed after the project's data expiration.
+
+### POSIX File Access
+
+!!!note "Mountpoints"
+ PROJECT file storages are accessible at mountpoints `/mnt/proj1`, `/mnt/proj2`, and `/mnt/proj3`.
+
+The PROJECT storage can be accessed via the following nodes:
+
+| Cluster | Node(s) |
+| ------------- | ----------------------------- |
+| Salomon | Login |
+| Barbora | Login, Compute, Visualization |
+| DGX2 | Compute |
+
+To show the path to your project's directory on the PROJECT storage, use the `it4i-get-project-dir` command:
+
+```console
+$ it4i-get-project-dir OPEN-XX-XX
+/mnt/proj3/open-XX-XX
+```
+
+### Project Quotas
+
+The PROJECT storage enforces limits (quotas) on projects' usage (used capacity and allocated inodes).
+Default quotas for capacity and amount of inodes per project are set by IT4Innovations.
+
+| Project default quota | |
+| --------------------- | ------ |
+| Space quota | 20TB |
+| Inodes quota | 5 mil. |
+
+Actual usage of the PROJECT storage (e.g. location of project directory, used capacity, allocated inodes) can be found in IT4Innovations' [SCS information system][b].
+
+### Lifting Project Quotas
+
+It is preferred that you request additional storage space allocation in advance in you application for computational resources.
+Alternatively, if the project is already active, contact [IT4I support][a].
+
+### Snapshots
+
+The PROJECT storage provides snapshot functionality. A snapshot represents a state of a filesystem at a particular point in time. Snapshots are created for all projects on fileset (i.e. project directory) level.
+Snapshots are created every day, snapshots older than seven days are deleted.
+
+Files in snapshots are accessible directly by users in the special subdirectory of each project directory named `.snapshots`.
+Snapshots are read-only.
+
+Snapshots' names have the `YYYY-MM-DD-hhmmss` format.
+
+```console
+[vop999@login1.salomon ~]# ls -al /mnt/proj3/open-XX-XX/.snapshots
+total 4
+dr-xr-xr-x. 2 root root 4096 led 14 12:14 .
+drwxrws---. 16 vop999 open-XX-XX 4096 led 20 16:36 ..
+drwxrws---. 16 vop999 open-XX-XX 4096 led 20 16:36 2021-03-01-022441
+drwxrws---. 16 vop999 open-XX-XX 4096 led 20 16:36 2021-03-02-022544
+drwxrws---. 16 vop999 open-XX-XX 4096 led 20 16:36 2021-03-03-022949
+drwxrws---. 16 vop999 open-XX-XX 4096 led 20 16:36 2021-03-04-023454
+drwxrws---. 16 vop999 open-XX-XX 4096 led 20 16:36 2021-03-05-024152
+drwxrws---. 16 vop999 open-XX-XX 4096 led 20 16:36 2021-03-06-020412
+drwxrws---. 16 vop999 open-XX-XX 4096 led 20 16:36 2021-03-07-021446
+```
+
+### ACL and File Permissions
+
+Access to a project directory and containing files is restricted by Unix file permissions and file access control lists (ACLs).
+Default file permissions and ACLs are set by IT4Innovations during project directory provisioning.
+
+## Backup and Safety
+
+!!!important "Data Backup"
+ Data on the PROJECT storage is **not** backed up.
+
+The PROJECT storage utilizes fully redundant design, redundant devices, highly available services, data redundancy, and snapshots. For increased safety, each disk array is connected in Distributed RAID6 each with two hot-spare disks, meaning it can recover full redundancy after two simultaneous disk failures.
+
+However, the storage does not provide data backup, so we strongly recommend using the [CESNET storage][1] for making independent copies of your data.
+
+<! --- (HA data replication?) -->
+<! --- (balancing in case of overload (data migration?) -->
+
+## Computing on PROJECT
+
+!!!important "I/O Intensive Jobs"
+ Stage files for intensive I/O calculations onto the SCRATCH storage.
+
+The PROJECT storage is not primarily intended for computing and it is strongly recommended to avoid using it directly for computing in majority of cases.
+
+On the other hand, the PROJECT storage is accessible from compute nodes and can be used for computing jobs with low I/O demands,
+when copying data to other storage for computing is not feasible or efficient.
+However, be aware of overloading the storage, as this will result in degraded performance for other users of the PROJECT storage or its unavailability.
+
+For maximum performance, you should always copy the files of I/O intensive jobs onto the SCRATCH storage.
+The files should be copied to SCRATCH from Login nodes before submitting the job.
+
+<! --- See also: data storage policy on filesystems (link?) -->
+
+<! --- ## Technical Specification -->
+
+<! --- For a detailed technical specification, see the Technical Specification section. -->
+
+## Summary
+
+| PROJECT Storage | |
+| -------------------- | ------------------- |
+| Mountpoint | /mnt/proj{1,2,3} |
+| Capacity | 15PB |
+| Throughput | 39GB/s |
+| IO Performance | 57kIOPS |
+| Default project space quota | 20TB |
+| Default project inodes quota | 5 mil. |
+
+[1]: ../barbora/storage.md#cesnet-data-storage
+
+[a]: mailto:support@it4i.cz
+[b]: https://scs.it4i.cz/projects
diff --git a/mkdocs.yml b/mkdocs.yml
index 2ec8238d95078085f9a18f22f2e5c0edb8ef463c..604d29c675c73dfaade3be1fe88f8cd3c861ab8a 100644
--- a/mkdocs.yml
+++ b/mkdocs.yml
@@ -69,6 +69,8 @@ nav:
- PRACE User Support: prace.md
- API Documentation: apiv1.md
- Withdrawal from service: anselm-salomon-shutdown.md
+ - Storage:
+ - PROJECT: storage/project-storage.md
- Clusters:
- Barbora:
- Introduction: barbora/introduction.md