One of the goals of this blog is to share the most useful EMC Isilon support-related content that we have to offer. In this post, we’re highlighting 20 of the most viewed knowledgebase (KB) articles and product documents from the month of March.
We hope these documents will help you to quickly find an answer to a common question or resolve an issue.
Top 10 KB articles
To access these KB articles, log in to the EMC Online Support site. Articles in bold are new to the top 10 list this month.
You’re rushing to meet a project deadline, and you need to update some related files that are stored on an EMC® Isilon® cluster. You’re working on a Linux computer, and you’re connected to the cluster over a Network File System (NFS) protocol. You need to access files in a directory that your coworker, who uses a Windows computer, created when they were connected to the same cluster over a Server Message Block (SMB) protocol. Thanks to the Isilon OneFS® operating system, you can seamlessly access your coworker’s files even though you are doing so through a very different protocol.
Supporting a mix of protocols requires supporting a mix of user identities and file permissions. This requirement can leave system administrators with several considerations when configuring OneFS.
Before discussing how OneFS handles multiprotocol file access, let’s first review how two operating environments, Windows and UNIX/Linux, authorize access to files. In a Windows environment, users are identified based on unique security identifiers (SIDs). Files or directories are secured through an Access Control List (ACL). In an UNIX environment, users and groups are identified through user identifiers (UIDs) and group identifiers (GIDs), respectively. Files are secured using POSIX mode bits.
OneFS uses Authentication, Identity Management, and Authorization (AIMA) to assign the right permissions and identifiers to users (and groups) no matter which protocols they use to connect to the cluster. To securely support NFS and SMB clients, OneFS does three things:
Connects to directory services, such as Microsoft Active Directory (AD) and Lightweight Directory Access Protocol (LDAP), which provides a security database of user and group accounts along with their information
Authenticates users and groups
Controls access to directories and files
When a user connects to an Isilon cluster, OneFS scans Active Directory and LDAP for the user’s identifiers. Once the user is authenticated, OneFS creates an access token for the user. OneFS then maps the user’s account (known as “user mapping” in OneFS) in one directory service to another. This single access token is the key to authorizing the user so they can access files that are stored and created on the cluster using different protocols.
For example, if a user, Mike, accesses a file share through SMB, OneFS will scan Active Directory and find an SID for him. If OneFS does not find any UIDs or GIDs associated with Mike via LDAP, OneFS will generate a UID and GID for him and save them to Mike’s access token, so he can access files created by NFS users.
The same type of mapping occurs for file permissions. If a file was created through SMB, it will be assigned an ACL to control who can access the file. OneFS will create equivalent POSIX mode bits for this file. File permissions can be saved to the Isilon cluster on disk in one of three modes: native, UNIX, or SID. For more information about each mode, and about AIMA and user mapping, read the “Identities, Access Tokens, and the Isilon OneFS User Mapping Service” white paper.
This is a brief summary of how multiprotocol file access works in OneFS. Watch the following video, “File Access Basics in an Isilon OneFS Multi-Protocol Environments,” for more information and recommendations for configuring multiprotocol access in OneFS. In this video, Principal Solutions Architect Amol Choukekar answers the following frequently asked questions:
What are multiprotocol basics?
How do Window and UNIX clients differ when they access files on OneFS?
How does OneFS handle user and group identities?
How does OneFS store file permissions in a multiprotocol environment?
How do clients access files that were created using a different protocol?
How does OneFS manage file permissions?
What if user names are not similar across authentication providers?
Review existing identity mappings stored on the cluster
Delete existing identity mappings
Review ACL policies on the cluster
Create a user mapping rule for joining different user names
This video also offers the following demonstrations:
File access between Windows and UNIX
Creation of a synthetic ACL, which dynamically maps UNIX permissions to Windows rights
File permissions management
For more information about implementing multiprotocol in OneFS, contact your account representative. If you have feedback about this blog or these videos, send an email to firstname.lastname@example.org. If you have a request for new documentation, send an email to email@example.com.
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