similar to: Checksum property change does not change pre-existing data - right?

I have some questions about the choice of SSDs to use for ZIL and L2ARC. I''m trying to build an OpenSolaris iSCSI SAN out of a whitebox system, which is intended to be used as a backup SAN during storage migration, so it''s built on a tight budget. The system currently has 4GB RAM, 3GHz Core2-Quad and 8x 500GB WD REII SATA HDDs attached to an Areca 8port ARC-1220 controller

Hi list, as this matter pops up every now and then in posts on this list I just want to clarify that the real performance of RaidZ (in its current implementation) is NOT anything that follows from raidz-style data efficient redundancy or the copy-on-write design used in ZFS. In a M-Way mirrored setup of N disks you get the write performance of the worst disk and a read performance that is

Under Solaris 10 on a 4 core Sun Ultra 40 with 20GB RAM, I am setting up a Sun StorageTek 2540 with 12 300GB 15K RPM SAS drives and connected via load-shared 4Gbit FC links. This week I have tried many different configurations, using firmware managed RAID, ZFS managed RAID, and with the controller cache enabled or disabled. My objective is to obtain the best single-file write performance.

http://hardware.slashdot.org/story/09/06/09/2336223/Apple-Removes-Nearly-All-Reference-To-ZFS

Hello, Im about to migrate a 6Tb database from Veritas Volume Manager to ZFS, I want to set arc_max parameter so ZFS cant use all my system''s memory, but i dont know how much i should set, do you think 24Gb will be enough for a 6Tb database? obviously the more the better but i cant set too much memory. Have someone implemented succesfully something similar? We ran some test and the

I''m working with a Cyrus IMAP server running on a T2000 box under Solaris 10 10/09 with current patches. Mailboxes reside on six ZFS filesystems, each containing about 200 gigabytes of data. These are part of a single zpool built on four Iscsi devices from our Netapp filer. One of these ZFS filesystems contains a number of global and per-user databases in addition to one sixth of the

If there were a ?zfs send? datastream saved someplace, is there a way to verify the integrity of that datastream without doing a ?zfs receive? and occupying all that disk space? I am aware that ?zfs send? is not a backup solution, due to vulnerability of even a single bit error, and lack of granularity, and other reasons. However ... There is an attraction to ?zfs send? as an augmentation to the

Interesting flash technology overview and SSD review here: http://www.anandtech.com/cpuchipsets/intel/showdoc.aspx?i=3403 and another review here: http://www.tomshardware.com/reviews/Intel-x25-m-SSD,2012.html Regards, -- Al Hopper Logical Approach Inc,Plano,TX al at logical-approach.com Voice: 972.379.2133 Timezone: US CDT OpenSolaris Governing Board (OGB) Member - Apr 2005

I''ve got a server that freezes when I run a zpool scrub from cron. Zpool scrub runs fine from the command line, no errors. The freeze happens within 30 seconds of the zpool scrub happening. The one core dump I succeeded in taking showed an arccache eating up all the ram. The server''s running Solaris 10 u3, kernel patch 127727-11 but it''s been patched and seems to have

Hi all Is it possible to securely delete a file from a zfs dataset/zpool once it''s been snapshotted, meaning "delete (and perhaps overwrite) all copies of this file"? Best regards roy -- Roy Sigurd Karlsbakk (+47) 97542685 roy at karlsbakk.net http://blogg.karlsbakk.net/ -- I all pedagogikk er det essensielt at pensum presenteres intelligibelt. Det er et element?rt imperativ

I encountered an issue that people using OS-X systems as NFS clients need to be aware of. While not strictly a ZFS issue, it may be encounted most often by ZFS users since ZFS makes it easy to support and export per-user filesystems. The problem I encountered was when using ZFS to create exported per-user filesystems and the OS-X automounter to perform the necessary mount magic. OS-X

The default blocksize is 128K. If you are using mirrors, then each block on disk will be 128K whenever possible. But if you''re using raidzN with a capacity of M disks (M disks useful capacity + N disks redundancy) then the block size on each individual disk will be 128K / M. Right? This is one of the reasons the raidzN resilver code is inefficient. Since you end up waiting for the

Hello, I am actually using ZFS under FreeBSD, but maybe someone over here can help me anyway. I''d like some advice if I still can rely on one of my ZFS pools: [user at host ~]$ sudo zpool clear zpool01 ... [user at host ~]$ sudo zpool scrub zpool01 ... [user at host ~]$ sudo zpool status -v zpool01 pool: zpool01 state: ONLINE status: One or more devices has experienced an

Hi, I''m atmost ready to deploy my new homeserver for final testing. Before I want to be sure that nothing big is left untouched. Reading ZFS Admin Guide About the checksum method, there''s no advice about it. The default is fletcher4. there''s also SHA256 Now the sha256 is pretty ''heavy'' to calculate, so I think that it''s left out because can

Today I updated the firmware on my StorageTek 2540 to the latest recommended version and am seeing radically difference performance when testing with iozone than I did in February of 2008. I am using Solaris 10 U5 with all the latest patches. This is the performance achieved (on a 32GB file) in February last year: KB reclen write rewrite read reread 33554432

Hello all, I understand that relatively high fragmentation is inherent to ZFS due to its COW and possible intermixing of metadata and data blocks (of which metadata path blocks are likely to expire and get freed relatively quickly). I believe it was sometimes implied on this list that such fragmentation for "static" data can be currently combatted only by zfs send-ing existing

Hello all... I''m seeing this behaviour in an old build (89), and i just want to hear from you if there is some known bug about it. I''m aware of the "picket fencing" problem, and that ZFS is not choosing right if write to slog is better or not (thinking if we have a better throughput from disks). But i did not find anything about 100% slog activity (~115MB/s) blocks

Hi, I don''t know if it''s already been discussed here, but while thinking about using the OCZ Vertex 2 Pro SSD (which according to spec page has supercaps built in) as a shared slog and L2ARC device it stroke me that this might not be a such a good idea. Because this SSD is MLC based, write cycles are an issue here, though I can''t find any number in their spec. Why do I

Hello, We have a new Thor here with 24TB of disk in (first of many, hopefully). We are trying to determine the bext practices with respect to file system management and sizing. Previously, we have tried to keep each file system to a max size of 500GB to make sure we could fit it all on a single tape, and to minimise restore times and impact should we experience some kind of volume

I have a Solaris 10 U5 system massively patched so that it supports ZFS pool version 15 (similar to U8, kernel Generic_141445-09), live upgrade components have been updated to Solaris 10 U8 versions from the DVD, and GRUB has been updated to support redundant menus across the UFS boot environments. I have studied the Solaris 10 Live Upgrade manual (821-0438) and am unable to find any