From mboxrd@z Thu Jan 1 00:00:00 1970 From: dexen deVries Subject: Split some metadata onto separate device? Date: Fri, 3 Jun 2011 12:29:33 +0200 Message-ID: <201106031229.38758.dexen.devries@gmail.com> Mime-Version: 1.0 Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma; h=domainkey-signature:from:to:subject:date:user-agent:x-face :mime-version:content-type:content-transfer-encoding:message-id; bh=wluI2UUv6dPCZcyvhQvD6KtCunTHMXK9adySH4NadpE=; b=tU547+WKzPpsF6vBiQ9NrPP0aMC8vCtKn29U982uRvpzg6smK9+yg+glV9BekKl8tL X+loK1wiIbjSjzVGkJI1W/eZDKRdtlI3M52RnunmTb2dQdKKvTiaMqHkVwrbpWPFu2AP vY6oRfcKceAglXXEUOC0YUcks7vvGCAKPk1vE= Sender: linux-nilfs-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-ID: Content-Type: text/plain; charset="utf-8" To: linux-nilfs-u79uwXL29TY76Z2rM5mHXA@public.gmane.org Hi list, back when I was using XFS, there was an option to put one particular pi= ece of=20 metadata -- the journal -- onto separate physical device. The speed-up = was=20 very significant, especially for operations on lots of files. For examp= le, with=20 external journal removing whole kernel source tree on XFS would take le= ss time=20 than on ext2 or ext3; with internal it would be much longer than ext2 o= r 3. The journal was needed only in case of unclean unmount, as only then it= =20 contained any information not applied yet; if the unmount was clean, th= e=20 journal contained no important information. XFS journals only metadata changes, btw. My question is, would it be feasible to move some part of NILFS2 metada= ta onto=20 separate device for R/W/GC speed-up?=20 Perhaps some of metadata could even be considered `recoverable' -- that= is, if=20 the other device gets broken or lost, the metadata on it could be re- constructed from content of the main device. Regards, --=20 dexen deVries [[[=E2=86=93][=E2=86=92]]] =46or example, if the first thing in the file is: an XML parser will recognize that the document is stored in the traditi= onal=20 ROT13 encoding. (( Joe English, http://www.flightlab.com/~joe/sgml/faq-not.txt )) -- To unsubscribe from this list: send the line "unsubscribe linux-nilfs" = in the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html