similar to: Centos/Linux Disk Caching, might be OT in some ways

Hello, I am running several virtualization servers with QEMU 1.4.x and libvirt 1.0.2 on Ubuntu 12.04 and am working on optimizing the cache= and aio= options for the virtual machines. These VM images are mostly qcow2, and are served both from a local ext4 filesystem (with data=ordered,barrier) and from an NFS mountpoint (with sync). The local filesystem sits on top of an md software RAID of SATA

Your question is difficult to parse. Typically RAID and JBOD are mutually exclusive. By "flash-backed", do you mean a battery backup unit (BBU) on your RAID controller? On Mon, Apr 9, 2018 at 8:49 AM, Vincent Royer <vincent at epicenergy.ca> wrote: > >> Is a flash-backed Raid required for JBOD, and should it be 1gb, 2, or 4gb >> flash? >> > > Is anyone

On 29 August 2007, "Ross S. W. Walker" <rwalker at medallion.com> wrote: > Message: 39 <snip> > I wouldn't worry too much about the OS HD configuration, you are > always going to want RAID1 for the OS, whether software or hardware. > > Reason I say not to worry too much about the OS HD config is because > you are almost certainly going to put the

Yes the flash-backed RAID cards use a super-capacitor to backup the flash cache. You have a choice of flash module sizes to include on the card. The card supports RAID modes as well as JBOD. I do not know if Gluster can make use of battery-backed flash-based Cache when the disks are presented by the RAID card in JBOD. The Hardware vendor asked "Do you know if Gluster makes use of

Has anyone worked with a x4500/x4540 and know if the internal raid controllers have a bbu? I''m concern that we won''t be able to turn off the write-cache on the internal hds and SSDs to prevent data corruption in case of a power failure. -- This message posted from opensolaris.org

I have a rather large box (2x8-core Xeon, 96GB RAM) where I have a couple of disk arrays connected on an Areca controller. I just added a new external array, 8 3TB drives in RAID5, and the testing I'm doing right now is on this array, but this seems to be a problem on this machine in general, on all file systems (even, possibly, NFS, but I'm not sure about that one yet). So, if I use

I have been trying to figure out whether I can enable write caching on my PATA hard drives (WD3200JB) and have fsync not return until data is safely on the platters. I am also running software raid. This is currently on FC5 (though soon to be FC6) with a 2.6.18 kernel. >From snippets I have found on the net, it looks like write barriers are pushed down through software raid when using raid 1.

I'm running Linux travis 2.6.15-1-686 #2 Mon Mar 6 15:27:08 UTC 2006 i686 GNU/Linux on a laptop with ext3 on / Some time ago things started getting weird in the following way: I do a fairly normal hack, ^Z, make, test loop when developing and it seems that vim is calling fsync or sync and that is then flushing everything to disk. My tests create maybe 10 dozen files in ~30MB and for some

All, Long ago Xen added code to the device model to basically do an fsync() after every data write if the user in the guest specified that IDE write caching should be disabled. This works fine, except in the case where you are doing O_DIRECT writes inside the guest (ala dd if=/dev/zero of=/dev/hdb oflag=direct). This is because you can get out of ide_write_dma_cb() in the middle of the loop

Hi All ; One of our customer is suffered from FS being corrupted after an unattanded shutdonw due to power problem. They want to switch to ZFS. >From what I read on, ZFS will most probably not be corrupted from the same event. But I am not sure how will Oracle be affected from a sudden power outage when placed over ZFS ? Any comments ? PS: I am aware of UPS''s and

My application always needs to sync file data after writing. I don't want anything handing around in the kernel buffers. I am wondering what is the best method to accomplish this. 1. Do I use EXT2 and use fdatasync() or fsync()? 2. Do I use EXT2 and mount with the "sync" option? 3. Do I use EXT2 and use the O_DIRECT flag on open()? 4. Do I use EXT3 in full journaled mode,

I'm using Samba to allow my users to store their database on a Redhat 6.1 file server. I've got some who want to shift to using Linux instead of Windows but the DBMS they use is not supported (yet... I'm told) on Linux and I'm afraid that multi-user access on different OS's are going to screw things all to high heck anyways... But that being said... Are there existing

Greetings, I am looking for a hardware raid card that supports up to 4 SATA II hard disks with hot swap (compatible raid cage) I have short listed two LSI/3Ware cards: 1. 9750-4i 2. 9650SE-4LPML Both appear to be well supported in Linux. I would appreciate your personal experience with the CLI tools provided by LSI. Can they be configured to send email for disk failures or SMART errors? Is

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Hi all, We are building a new system which is going to use ext3 FS. We would like to know more about the behavior of ext3 in the case of failure. But before I procede, I would like to share more information about our future system. * Our application always does an fsync on files * When symbolic links (more specifically fast symlink) are created, the host directory is also fsync'ed. * Our

I didn''t see anyone post a link to David''s Interview by Lenz here on the list so I decided to post it. The interview can be accessed here: http://dev.mysql.com/tech-resources/interviews/david-heinemeier-hansson-rails.html I was very happy to see the interview on PlanetMySQL as just the other day I was talking about RubyOnRails on my MySQL blog which is syndicated

Hi all. We just put a relative large server in operation (for our measures ;-) ), a 4x Dual Core / Intel with 16GB Ram and a 3ware 9550SX SATA-RAID with 4 drives. Operating system for the Dom0 is an up-to-date gentoo linux. Everything runs really fine, there are 4 Domu''s running, 1x gentoo and 2x debian and 1x Windows Server 2003. DomU''s are running blazing fast in normal

Raghavendra, Thanks very much for your reply. I fixed our data corruption problem by disabling the volume performance.write-behind flag as you suggested, and simultaneously disabling caching in my client side mount command. In very modest testing, the flock() case appears to me to work well - before it would corrupt the db within a few transactions. Testing using built in sqlite3 locks is

Thank you for your help. Le 05/01/2015 19:10, John R Pierce a ?crit : > works here fine on the 9261, which is an OEM version of the same card > with the connectors in a different orientation... you might check your > LSI firmware revision. My firmware seems to be more up to date. Anyway, I will try to update firmware. I have to check how to do that. # dmesg |grep LSI scsi4 : LSI SAS

I have a trio of servers that like to reboot during high disk / network IO operations. They don't appear to panic, as I have kernel.panic = 0 in sysctl.conf. The syslog just shows normal messages, like samba complaining about browse master and then just syslogd starting up. The machines seem to crash when I'm not near the console, usually when I'm trying to pull data off them to