The OmniStor smart storage platform supports two architectures: standalone and HA. Platform administrators can use OmniStor Manager (OSM)'s Storage settings to switch individual physical Drive operating modes (Normal ↔ Read-Only) for maintenance, capacity planning, and hardware replacement. This article covers the storage architecture concepts, how to use the OSM Storage settings interface, the impact of mode switches under each architecture, and the file migration procedure for server hardware issues.

This article corresponds to OSM Administrator Manual section 2.2.6 "Storage Management." For full operating screenshots and details, refer to that manual.

Core storage architecture concepts

Before working with Storage management, understand these three layers:

Easy mnemonic: Storage Pool → Storage Group → AMOS → Drive.

Standalone vs HA architecture

OmniStor supports two architectures, differing in number of copies and consistency guarantees.

Standalone architecture

• Composition: 1 Storage Group + 1 AMOS.
• Copies: One copy only of each file.
• Write flow: file → Storage Group → the single AMOS → AMOS chooses to write to one of D:\ or E:.
• Best for: development, testing, budget-sensitive small deployments.

HA architecture

• Composition: ≥ 1 Storage Group. AMOSes within each Storage Group are designed as pairs living on different host machines.
• Copies: Each file is stored as two copies on different hosts.
• Write flow: file → Storage Pool manager selects a Storage Group based on load → the Storage Group writes the file to both paired AMOSes → each AMOS decides which Drive on its host machine to write to.
• Consistency: Maintained through cooperation between paired AMOSes within each Storage Group.
• Best for: production environments requiring high availability and data protection.

The Storage settings interface

Navigate to Platform Management → Storage Management → Storage Settings to see the physical Drive status list, including:

• Licensed Space: The total licensed capacity your organization has (e.g., 5.00 TB).
• Total Physical Space: Combined physical capacity of all Drives, used amount, and usage percentage.
• DriveGroupId: Identifier of the Storage Group — paired Drives share the same DriveGroupId.
• IP: The host IP where the Drive lives (used to determine pair relationships).
• Drive Name: The drive letter (e.g., D, E).
• Available Space (%): Remaining capacity percentage on the Drive.
• Status: Current operating mode (Normal / Read-Only).
• Time Stamp: When the status last changed.

Paired display under HA

Under HA, physical Drives appear as pairs. For example:

Rows with the same DriveGroupId are a pair. Acting on D of 192.168.1.161 automatically links to D of 192.168.1.162.

Two color indicators

Text color in the list reflects Drive state:

• Orange text: The Drive is in Maintenance mode — switched to read-only.
• Specific other color: Heartbeat check error — the host failed a heartbeat check; investigate immediately.

Switching Drive operating mode (Normal ↔ Read-Only)

Steps

1. Sign in to OSM. Go to Platform Management → Storage Management → Storage Settings.
2. Find the target Drive and click the "Normal" or "Read-Only" text in its Status column.
3. A dialog appears asking for the reason for the operation (e.g., "Disk replacement," "Capacity expansion").
4. Click OK to apply the mode change.
5. After the switch:
   • The Status field changes from "Normal" to "Read-Only" (or vice versa).
   • The entire row's text turns orange (maintenance mode) or back to normal.

Linked switching under HA

Important: Under HA, switching any one Drive automatically switches its paired Drive (same DriveGroupId) on the other host. For example, switching D on 192.168.1.161 from Normal to Read-Only will also switch D on 192.168.1.162 to Read-Only.

This is by design to keep the two copies in sync — you cannot read-only just one half of a pair.

Impact of switching to Read-Only mode on users

Under standalone architecture

• A Drive in read-only mode: rejects new uploads but still serves downloads.
• New uploads go to other Drives still in normal mode.
• If every Drive in the entire AMOS is read-only: Users can no longer upload via any client (Web, mobile apps, Sync Client, OmniStor Drive). Downloads still work.

Under HA architecture

• A Drive in read-only mode and its paired Drive: Neither location accepts new writes, but both serve downloads.
• The system picks another Storage Group still in normal mode to handle new uploads.
• As long as at least one Storage Group has all its Drives in normal mode, the overall upload function isn't interrupted.

Common admin scenarios

Scenario 1: Replacing a disk on a host

Standard flow under HA:

1. In OSM, switch the target Drive to Read-Only (its paired Drive switches together).
2. Confirm no writes are happening to that Drive, and users haven't noticed anything (the paired Drive still serves downloads).
3. Perform the hardware replacement.
4. After replacement, depending on situation:
   • If the new disk needs data backfill → see "SD file copy/migration" below.
   • Once data is in place, switch back to Normal mode in OSM (paired Drive switches together).

Under standalone: Without copy protection, disk replacement requires careful backup and restore planning. Take a complete backup beforehand.

Scenario 2: A Drive is nearly full

• HA: Consider adding a new Storage Group to share the load — no need to touch existing Drives.
• Standalone: Add a new physical Drive to the existing AMOS, or consider migrating to HA.

Scenario 3: Planning a service maintenance window

• If you need read-only mode during the window: switch the target Drive(s) to read-only. Users can still download but not upload.
• After service maintenance ends, make sure every Drive is switched back to Normal — this is a common oversight.
• Fill in a clear "operation reason" when switching, so you can trace it later in the audit log.

Scenario 4: Heartbeat check error detected

• Check that host's network and hardware status immediately.
• Under HA, the paired Drive still serves, but your HA protection level is temporarily degraded — restore as quickly as possible.
• The text color in the Storage settings view tells you which Drive is having trouble at a glance.

Advanced: file migration when an SD Server host has issues

When an SD Server (the host machine for a Storage Group) has issues or needs upgrading, you may need to migrate files from that host to another. The OSM manual recommends using RichCopy for file copy/migration.

Before you start

• The Storage Group whose files you're copying/migrating must be set to Read-Only in OSM.
• The destination Disk must be formatted and empty.

Tool and installation

• Get the installer: RichCopy installer.
• Where to install: Either source or destination host works; destination host is recommended.

Set up network drives

Map the source (or destination) host's disks as network drives. For example:

• Source host: 172.17.5.35 (RichCopy installed here)
• Destination host: 172.17.5.46
• Map destinations as network drives:
  • \\172.17.5.46\d$ as Disk Z
  • \\172.17.5.46\e$ as Disk Y

Open RichCopy and configure copy parameters

Important caveat: Don't use the disk-picker dropdowns on the right side of RichCopy — SD Servers have so many files and directories that the dropdowns can crash when expanding directories.

For full RichCopy parameter details, see the appendix of the OSM manual.

Things to keep in mind

Before the operation

• Fill in a clear operation reason: Every mode switch is logged. Clear reasons make later auditing and troubleshooting much easier.
• Under HA, understand the linked switch: Acting on D of 192.168.1.161 will also affect D of 192.168.1.162. This is a protection design, but it can surprise you if you didn't know.

After the operation

• Verify the mode switch succeeded: Confirm via both the Status text and the row color.
• Notify affected teams: If the switch affects user experience (such as all Drives going read-only), notify users in advance and schedule a service announcement.
• Audit regularly: Use OSM's Platform Admin Operation Log to periodically review Storage settings changes.