Diskruimte

Diskspace

The diskspace on C&CZ servers can be used from all kind of C&CZ servers and personal computers, but also from other PCs or even from home with WinSCP or VPN. Almost all disks that are managed by C&CZ, are being backupped regularly, in order to be able to restore data in case of small or large calamities.

Home directories

Every user with a Science login has or is entitled to an amount of disc space of a few Gigabytes on a server. This disc space is called the "home-directory" on Unix/Linux computers and the "H- or U-drive" on Windows-computers. The location of this homedirectory (which server) can be viewed on the Do-It-Yourself website.

Naming

Username	guest204
SMB (Windows/...) name	\\home1.science.ru.nl\guest204 or \\home2.science.ru.nl\guest204 check on DIY
URL (Apple/Linux/Android/...) name	smb://home1.science.ru.nl/guest204 or smb://home2.science.ru.nl/guest204 check on DIY
NFS (C&CZ beheerd Linux) name	/home/guest204

Access rights

Long ago the (Unix) home directory of a user, except for a few protected areas, was readable for all users of the server. Today the home directory of a user can be accessed by the user himself. The user can change the access rights. C&CZ checks for home directories that are writable by other users.

Access through NFS

Mounting a home (U:) drive on Linux via NFS/Kerberos.

Functionality and costs of network shares

RAID server shares

Diskspace for groups/institutions/projects: there are a few fileservers with RAID storage with partitions that can be rented for a period of 3 years. The price for new discs or a new 3 year extension of an older disc is per July 2018 for FNWI departments:

size	incl. backup	without backup
ca. 200 GB	€ 40 per year	€ 10 per year
ca. 400 GB	€ 80 per year	€ 20 per year

Although even the cheapest version is much more expensive than buying 1 disk for 1 PC, it often makes sense, because of the reliability (redundant disks, backup, support contract) and security (stable server). One or more folders on such a partition can be mapped as a network drive on Windows PCs or NFS-mounted on Unix/Linux hosts. The ability to read and/or write files on these folders can be limited to a group of logins. That group can be managed by the department on the Do-It-Yourself website.
C&CZ has service contracts for these servers and has spares on site, so a failure can be resolved quite fast. Because the disks are part of a RAID set, the failure of 1 single disk or even 2 disks, will not give a disruption of service for users. The partitions are backed up (daily and incremental). Even in the case when the whole server room is lost, data can (eventually) be restored.

Ceph Storage

Starting November 2019 we can provide almost unlimited storage for the Faculty of Science using our Ceph storage cluster. The way Ceph works there is a tradeoff for performance and redundancy. Also it is possible to improve redundancy above single server RAID-6 level, with the additional redundancy options. NB Ceph volumes have no backups, the volumes tend to be too large to backup

Pool	why	price per TB per year without backup
Erasure coding 8+3	cheap	€ 45
Erasure coding 5+7	cheap + additional redundancy	€ 80
3 copy	faster r+w	€ 100
4 copy	faster r+w + additional redundancy	€ 135

The Ceph storage can be used as windows share, nfs share or S3 object store. Object store is a different concept than a normal filesystem, so data stored in a windows or nfs share cannot be accessed using the s3 protocol.

The performance properties of Ceph are different from traditional single server storage; write speed usually exceeds read speed and lots of small files is killing for throughput, even worse than on traditional storage.

NB, 1 TB is 1.000.000.000.000 bytes

Naming

Volume name	sharename
SMB (Windows/..) name	\\sharename-srv.science.ru.nl\sharename
URL (Apple/Linux/Android/...) name	smb://sharename-srv.science.ru.nl/sharename
NFS (C&CZ-beheerd Linux) name	/vol/sharename

Access rights

Most of the shared disks can be read and written by a specific group of users. The owners of this group can administer on the Do-It-Yourself website which accounts are a member of this group.

Requests

A request for one or more network discs should contain:

• requested name of the disc(s)
• requested size (max ca. 500GB with backup)
• possibly requested backup schedules to lower the price (Daily/Monthly/Yearly)
• Science loginname of an owner
• possibly Science loginname of a member
• charge account (kostenplaats) or project code for the costs in the first three years.

Temporary shared diskspace

Every now and then you want to send one or more large files (more than a few tens of MBs) to someone else within the Faculty, mail is unsuited for those large files. To make this easy, one can use a network share, where one can store large files temporarily in order to have someone else copy the files from this location. Note that this is explicitly meant for temporary storage, we do not make backups of this share, every day we remove files older than 21 days old. When copying files to this share, make sure the file timestamps are updated. Some copy programs (like rsync) maintain the original timestamps and older files will be deleted. To update timestamps, you can use the following command:

find . -exec touch {} +

This share can also be used to store temporary files only readable for yourself by using a different name for the share. Note that also in this case, old files will be removed.

Please create a subdirectory with your name first, and put your files in that directory.

For files totaling less than 250GB, also Surfdrive is an alternative. For sending files up to 500GB SURFfilesender can be used.

Naming

Volume name	temp
SMB (Windows/..) name	\\temp-srv.science.ru.nl\share or \\temp-srv.science.ru.nl\onlyme
URL (Apple/Linux/Android/...) name	smb://temp-srv.science.ru.nl/share or smb://temp-srv.science.ru.nl/onlyme
NFS (C&CZ-beheerd Linux) name	/vol/temp

Access rights

• Readable by all users: share
• Only readable for the owner: onlyme