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Hi, I have installed Xen on Linux 2.6.11.10 <http://2.6.11.10> and i am trying to do Asynchronous Direct IO on SAS drives. The application which does the asynchronous direct io on SAS drive is running on Domain 0. Actually the IOPs what i get for a 512Bytes IO size is 67, but if i do the same operation on Linux 2.6.11.10 <http://2.6.11.10> native kernel, i get 267 IOPs.Cananyone tell me why this huge differnece? Am i missing something? In the current setup on Xen, if i do Synchronous IO, then i am getting 265 IOPs which is expected. So i am wo...

Hello, can someone give me a short summary on the status of support for sector sizes >512bytes in SYSLINUX? The installer obviously still doesn't support it, at least it complains about "unsupported sector size" when used on a 4k-sector disk. I read somewhere that this is only a problem of the installer, and that SYSLINUX itself would work if it got installed "by other to...

Hi list, I'm building a NFS server on top of CentOS 8. It has 8 x 8 TB HDDs and 2 x 500GB SSDs. The spinning drives are in a RAID-6 array. They are 4K sector size. The SSDs are in RAID-1 array and with a 512bytes sector size. I want to use the SSDs as a cache using dm-cache. So here what I've done so far: /dev/sdb ==> SSD raid1 array /dev/sdd ==> spinning raid6 array I've added "allow_mixed_block_sizes = 1" to lvm.conf to be able to add sdb and sdd in the same VG (because of the...

...nux). One way works, the other way does > not... For starters, what version? Official pre-compiled binaries? > Use Case 1: > In this scenario, Linux is installed to its *own* partition as is > syslinux (syslinux -i /path/to/syslinux/files). Afterwards, I 'dd' > the first 512bytes of that partition as the .bss file to chainload > from the host OS bootloader. This method works for all tested host > OS's including Windows. > > > Use Case 2: > In this scenario, Linux is installed to the *same* partition as the > host OS. If the host OS is Linux, I jus...

...installed either to its own partition, or to the partition of a host OS (Windows or Linux). One way works, the other way does not... Use Case 1: In this scenario, Linux is installed to its *own* partition as is syslinux (syslinux -i /path/to/syslinux/files). Afterwards, I 'dd' the first 512bytes of that partition as the .bss file to chainload from the host OS bootloader. This method works for all tested host OS's including Windows. Use Case 2: In this scenario, Linux is installed to the *same* partition as the host OS. If the host OS is Linux, I just add the option of booting our s...

...Background: I have a ZFS volume with the incorrect volume blocksize for the filesystem (NTFS) that it is supporting. This volume contains important data that is proving impossible to copy using Windows XP Xen HVM that "owns" the data. The disparity in volume blocksize (current set to 512bytes!!) is causing significant performance problems. Question : Is there a way to change the volume blocksize say via ''zfs snapshot send/receive''? As I see things, this isn''t possible as the target volume (including property values) gets overwritten by ''zfs receive...

Hi, > Hi list, > > I'm building a NFS server on top of CentOS 8. > It has 8 x 8 TB HDDs and 2 x 500GB SSDs. > The spinning drives are in a RAID-6 array. They are 4K sector size. > The SSDs are in RAID-1 array and with a 512bytes sector size. > > > I want to use the SSDs as a cache using dm-cache. So here what I've done > so far: > /dev/sdb ==> SSD raid1 array > /dev/sdd ==> spinning raid6 array Looks like you're using a hardware raid controller, right? > > I've added "allow_...

Hi, There is any way to figure out where physically is the journal on a ext3 fs and it's size? Thanks! Jordi

...write several small programs which execute before the OS takes control. Today; I have a "bootloader" which copies the original bootsector to an unused location on the hard drive; then puts itself into the exiting bootsector. This loader is ofcourse limited like any boot sector to <<512bytes... and I'm have zero space to add needed features. If this sounds like a virus; it was... I took the stoned virus example and crippled it so it only infects one HD when executed as a standalone c++ program... after several user prompts and confirmations. The problem I'm running into is tha...

I''ve been trying to migrate a win nt 4 machine to a xen domu for the past few months with no success. However, on my current attempt, the original hardware no longer boots, so I''m trying to resolve the issues with xen properly, or else take a long holiday... Anyway, the physical machine had a 9G drive (OS drive), a 147 G drive (not in use) and a 300G drive (all SCSI Ultra320 on

Here are patches to do offline deduplication for Btrfs. It works well for the cases it''s expected to, I''m looking for feedback on the ioctl interface and such, I''m well aware there are missing features for the userspace app (like being able to set a different blocksize). If this interface is acceptable I will flesh out the userspace app a little more, but I believe the

In blkback driver, after I/O requests are submitted to Dom-0 block I/O subsystem, blkback goes to ''sleep'' effectively without letting blkfront know about it (req_event isn''t set appropriately). Hence blkfront doesn''t notify blkback when it submits a new I/O thus delaying the ''dispatch'' of the new I/O to Dom-0 block I/O subsystem. The new I/O is

Guys, I've heard about some absurd RAM requirements for 9.1, has anybody tested it? e.g. http://forums.freebsd.org/showthread.php?t=36314 -- View this message in context: http://freebsd.1045724.n5.nabble.com/9-1-minimal-ram-requirements-tp5771583.html Sent from the freebsd-stable mailing list archive at Nabble.com.

Hi all, I add a blkback QoS patch. You can config(dynamic/static) different I/O speed for different VM disk by this patch. ---------------------------------------------------------------------------- diff -urNp blkback/blkback.c blkback-qos/blkback.c --- blkback/blkback.c 2011-06-22 07:54:19.000000000 +0800 +++ blkback-qos/blkback.c 2011-06-22 07:53:18.000000000 +0800 @@ -44,6 +44,11 @@

Hi all, I add a blkback QoS patch. You can config(dynamic/static) different I/O speed for different VM disk by this patch. ---------------------------------------------------------------------------- diff -urNp blkback/blkback.c blkback-qos/blkback.c --- blkback/blkback.c 2011-06-22 07:54:19.000000000 +0800 +++ blkback-qos/blkback.c 2011-06-22 07:53:18.000000000 +0800 @@ -44,6 +44,11 @@

...uests on a given underlying block device use up their + tokens. + + There are two policies for token consumption. One is that a token is + consumed for each I/O request. The other is that a token is consumed for + each I/O sector, for example, one I/O request which consists of + 4Kbytes(512bytes * 8 sectors) read consumes 8 tokens. A user can choose + either policy. + + With this approach, a job running on an ioband group with large weight + is guaranteed a wide I/O bandwidth. + + -------------------------------------------------------------------------- + +Setup and Installation...

...uests on a given underlying block device use up their + tokens. + + There are two policies for token consumption. One is that a token is + consumed for each I/O request. The other is that a token is consumed for + each I/O sector, for example, one I/O request which consists of + 4Kbytes(512bytes * 8 sectors) read consumes 8 tokens. A user can choose + either policy. + + With this approach, a job running on an ioband group with large weight + is guaranteed a wide I/O bandwidth. + + -------------------------------------------------------------------------- + +Setup and Installation...

...uests on a given underlying block device use up their + tokens. + + There are two policies for token consumption. One is that a token is + consumed for each I/O request. The other is that a token is consumed for + each I/O sector, for example, one I/O request which consists of + 4Kbytes(512bytes * 8 sectors) read consumes 8 tokens. A user can choose + either policy. + + With this approach, a job running on an ioband group with large weight + is guaranteed a wide I/O bandwidth. + + -------------------------------------------------------------------------- + +Setup and Installation...

...hat have requests on a given + underlying block device use up their tokens. + + The weight policy lets dm-ioband consume one token per one I/O request. + The weight-iosize policy lets dm-ioband consume one token per one I/O + sector, for example, one I/O request which consists of 4Kbytes (512bytes * + 8 sectors) read consumes 8 tokens. + + With this approach, a job running on the ioband group with large weight + is guaranteed a wide I/O bandwidth. + + -------------------------------------------------------------------------- + + range-bw policy + + range-bw means the predicabl...

...hat have requests on a given + underlying block device use up their tokens. + + The weight policy lets dm-ioband consume one token per one I/O request. + The weight-iosize policy lets dm-ioband consume one token per one I/O + sector, for example, one I/O request which consists of 4Kbytes (512bytes * + 8 sectors) read consumes 8 tokens. + + With this approach, a job running on the ioband group with large weight + is guaranteed a wide I/O bandwidth. + + -------------------------------------------------------------------------- + + range-bw policy + + range-bw means the predicabl...